You’ve told me you have to compress your arms against your chest to use an ortho, and that you have blatant ulnar deviation while doing so.
The only way those two add up, is if you are trying to keep your arms perpendicular to the keyboard rows.

Here’s picture of my right arm, in typing position, on my Preonic.
Notice that my wrist is straight, even though my arm is coming in at an angle.
You can’t really tell from the overhead picture, but it is also straight vertically because I float my hands over the keyboard, like a pianist.

https://preview.redd.it/8sz1ohe48j2c1.jpeg?width=1445&format=pjpg&auto=webp&s=1ea2b450428307f9234aec6a9b1cdcb95807e91f

As I told the other user above, the only thing that matters here is that you keep your wrists straight, with respect to your forearms.
Do that however you want, with whatever you want.

Columnar stagger is exactly the same as ortho, and traditional stagger splits are nearly as bad as traditional stagger on a single board setup.

The be-all, end-all of this discussion is whether you keep your wrists straight, as referenced from your forearms.
How you choose to do that is up to you.

Imagine having a piece of diamond-coated piano wire running through a wooden hoop.
As long as you pull the wire straight, nothing happens to the wood.
If you pull one end, or the other, out of alignment, the wire starts sawing at the wood.

That is a very good simulacrum of your carpal tunnels.
As long as there is minimal contact between your tendons, and the surrounding bones, you are good.
The tendons contact the bone, get irritated, then inflamed, and begin pushing against the nerves, which is what causes the intense pain.

Your wrist angle, compared to the board itself, is not the important part of this issue.
It’s your wrist angle, compared to your forearm that causes issues.

Straighten that out in whatever manner works best for you.

Standard stagger turns your left wrist outward, as you ascend the rows, which is what creates ulnar deviation.

Ortho, with proper form, does not create this condition because there is no outward stagger to the keys forcing you to chase them.
Your fingers should travel straight up and down the columns, which does not require any deviations in the wrist to accomplish.

There is no “less space from key to key” with ortho.
The keys are spaced exactly the same as they are on a standard layout, they are just aligned differently.

Your own form is causing you to misinterpret my claim to straight wrists.
As I mentioned in my previous post, my wrists are straight with respect to my forearms.
My upper arms are at a comfortable distance from my chest, and angling outward from my body.
My forearms make the return trip to the keyboard at maybe a 20 degree angle to the board.
My fingers stagger, to align themselves to the rows.

You, by contrast, are trying to align your wrists to the keys themselves, which is terrible form for typing.
That is why you have to uncomfortably compress yourself, and/or bend your wrists outward, to align to the keyboard.

I have no idea what you’re talking about with your “turn your wrists” comment.

My wrists are perfectly straight, with respect to my forearms, both horizontally and vertically, when using any of my orthos, including my Preonic.
I make all the alignment adjustments with my fingers, just like I do when playing guitar or bass.

Columnar stagger is OK, but is exactly the same as ortho, with respect to wrist position.
You just have to reach farther for some keys, which doesn’t affect wrist alignment, when done properly.

Splits, assuming you are still using some form of straight line layout with them, do not change your wrist positions either.
They change the alignment of your elbows and shoulders.
Standard stagger splits have exactly the same issues as a single board standard stagger, with respect to your left wrist having to turn outward.

I realize that.

I just feel somewhat compelled, as an actual “southpaw”, to point out the fallacies associated with the name.

I wouldn’t want any of my fellow southpaws to buy into the name, without taking the time to examine the functionality of the product being offered.

I like Topre switches, but don’t care for the actual HHKB layout, so I made my own.

The first thing to go was the antiquated staggered layout.
There’s absolutely no reason for that to still exist.
A keyboard is not a manual typewriter.
The keys aren’t going to get stuck, if you type too fast.

My layout retains all the good features from the original, like the split backspace, but it adds a numpad, splits the spacebar, and fixes the issues with the arrow keys, all in the same footprint.

https://preview.redd.it/fxyq30h4162c1.jpeg?width=3811&format=pjpg&auto=webp&s=7f71cdd5b3580642849c9e5180b5b5f5204b5090

For me, you’re missing out on the efficiency of a properly thought out layout, and the ability to alter the keymaps, through layering and characters swapping, to make your keyboard truly your own.

The keyboard you have is decent, but it is literally the “same thing everyone else has”, with very minor tweaks, to remove the spacing between some of the keys.
By contrast, I have all those same features, fit into a 60% case, and have the ability to alter the keymap however I want on top of that.

Here’s a pic of my work board, so you can better understand what I’m talking about here.

https://preview.redd.it/0h1h9q9lt52c1.jpeg?width=3811&format=pjpg&auto=webp&s=a8d4b39a58e118d0f8cba75b48dcbd8efcf2a1aa

For day-to-use, my keyboard allows me to put frequently used features closer to the home keys, so I don’t have to move my hands all over a larger board, to get to them.
Most notably, it allows me to put the numpad directly over my right hand alphas, so I can switch back and forth from numbers to letters, on the fly, without moving either hand from its home position.

For gaming, it allows me to create custom keymaps, to fit my needs in a specific game, should I need to do so.
This feature is especially important when you hit one of those games where the designers were too lazy to include the ability to alter the controls.
Don’t like the fact that a particular game forces you to use the arrow keys for movement?
A good programmable keyboard will allow you to program your WASD keys to send the arrow characters, solving the problem.

For me, endgame is when you are in a position where you look at all the “new” stuff being offered, and are able to honestly say, “but that’s not as good for me as what I already have”.
I’ve hit that point with my two customs.
The keyboards I have are designed by me, for me to use in specific locations.
That’s something you can’t just run out and buy off the shelf.

Budget doesn’t necessarily play into this either.
If you ignore the amount of money I’ve spent on keycaps, my builds are relatively inexpensive, but offer premium components.

Why does everyone keep calling these “southpaw” keyboards?

A true “southpaw” setup will have the mouse on the left side of the keyboard, which would make the standard layout the “southpaw” one.
As proof of this, I would point to the posts by several people in the comments here who are right-handed, and have finally discovered that the standard layout is ass-backward for them, if they want to keep their hand on the mouse.

On the good side, it’s nice to see right-handed people starting to question “how we always done it”, and creating their own solutions for the problems they encounter.
That’s just how life has always been, for us left-handers.

I’m on the opposite end of this spectrum from you.

I prefer lighter weight springs for exactly the reasons you are looking to achieve here.
The heavier a spring you put into a tactile switch (or in this case clicky switch), the less pronounced the tactile bump will be.

To keep the math really simple here, let’s suppose a given tactile bump adds 35g to the linear resistance of a switch, when you encounter the bump.
If you are starting with a 70g spring, that bump will only be adding 50% to the overall resistance of the switch.
If you swap that spring down to 35g, in that same switch, the bump is suddenly adding 100% to the resistance of the switch, making the bump feel much more pronounced.
Again, these numbers are very simplified, but the principle holds true.

And, my answer to your Happ vs. Sanwa dilemma is flat top Seimitsus.
I discovered those when I bought a Jaleco Pony cab years ago, and haven’t looked back since.

I would suggest taking a look at ortho boards.

Ortho boards are more versatile than traditional stagger boards, especially as the sizes get smaller.
As another user has mentioned, you can fit up to 75 keys into the same footprint as a standard 60% board.

I have two different 69-key layouts based on that idea, both with numpads layered over the right hand alphas, and couldn’t be happier with them.
With the numpads located directly over the right hand alphas, I can swap back and forth between letters and numbers, at will, without having to relocate either hand.