In Windows, you can't run a command line underneath the OS anymore, not since... Windows NT or 2000? And the registry remappings are so low level that they'll work anywhere.

So yeah, this problem is a pretty Linux specific one. Without XKB you can't do the advanced things I like, so xmodmap alone is not an acceptable solution. But for the terminal consoles I guess you may need it.

Colemak mod-dh is marvelously good. I use it to type everything. Thank you for that.

I was looking at your Extend Layer AutoHotkey scripts, and was wondering how can I change the toggle key from capslock to space, but can still issue a space with "space down and then up without key presses in between", like touchcursor? My autohotkey knowledge is limited. It'd be great if you could kindly point me the direction. Thank you. :)

Glad DH is working for you!  My AutoHotkey scripts don't support dual-role modifiers, but I have seen this done in other AHK scripts so I believe it is possible. I'm not an AHK expert either, and anyway am mostly using Linux these days, so can only recommend looking up other sources. Or use EPKL as DreymaR says.

Mind you, when I have experimented previously with dual-mode space, I found that it doesn't work very smoothly once your typing reaches a certain speed as you tend to hit space then the subsequent letter quickly enough that the key-up and key-down events are not necessarily in the right order. So personally I am skeptical of this approach and prefer dedicated keys for important keys like Space and Extend. Dual-mode might be OK for lesser used keys though.

@stevep99 To use Tap-or-Mod keys, you have to use timers and key interrupt routines so that if you type something else before releasing the ToM key it'll be interpreted as a tap not a wait unless the timer is up in which case it'll be a modified stroke instead. I took a page from the TMK code to see the importance of this. Even so, I haven't managed to make those fancy ToM keys on S/T & N/E (LShift/LCtrl & RCtrl/RShift) that I saw someone on the Discord use. At high speed, the key sequence got jumbled as you say. One challenge is that you expect a Shift to take very quickly so you can't have anywhere near a generous timer for it (and you can't use Sticky Shift on a ToM, obviously). In contrast, I've hardly had any trouble at all with the Caps key as ToM Mother-of-DeadKeys / Extend.

Seems to me that the QMK/TMK people have cracked this problem, so I guess we'll have to ask them how it can be done robustly. Dusty at the Discord uses home row tap-or-mod keys, and he finds them great it seems.

Some interesting projects there. I even cloned touchcursor-linux to try it out and it worked! However as far as I can tell, there's no clever timer-based configuration as per DreymaR's mentionings. It's also interesting that you can select by specific keyboard name if you have more than one connected.  Coincidentally I came across this video recently, where this would have solved his problem, but he mentions specifically about not using linux about half way through.