GKey VS taipo2

As far as I am aware people have made German: https://github.com/Rion96/GKey and Brazilian: https://github.com/erickweil/TempleOS-Stuff keyboard layouts.

Yeah taipo might be what you're looking for. It's a chorded input system that fits all ascii(?) characters on just 8 keys, fully mirrored on each hand. It's modeled after artsey but is better optimized. There's the github page, an image that might have more visual clarity and finally a typing demonstration which I think is the fastest ascii test ever recorded actually

Yes, there are people out there who have written multiple extensive command-line utilities to analyze and optimize keyboard layouts. Yes, there are people who have hit 220 wpm typing speeds on a typing test where the layout changes in the middle... twice. There are people who have written 80 whole pages on everything you could possibly want to know about why modern layouts are designed the way they are. But actually, that just covers the basics. We have extra keys on your thumbs, we have shift keys that you only have to tap instead of holding down, we have keys that change depending on what you previously typed, we even have layouts that don't work anything like a normal keyboard.

You might be interested in Taipo2, it's an optimized version of artsey which should work pretty all right on one hand. It's got barely any movement because it only has 8 keys, so you might even be able to incorporate your second hand into it at some point (if everything heals as well as the doctors say it will which we hope for!). There's also Soar which is a 17 chorded key layout and seems pretty promising. I'm pretty sure dvorak L and R are actually fairly decent onehanded layouts, afaik there's not much new tech out there though. Good luck!