Disclaimer: not an UI/UX-pro, just a Linux-pro. But I can throw in some workarounds. Currently I'm struggling with too much windows, not wanting to use virtual desktops, because there must be something better (or just lazy), and possible hammer-nail POV.
Get a second GPU (or repurpose your iGPU), install Linux, virtualize Windows with passing the main GPU to it. Overhead? 5FPS (in ~2015 FPS).
Personally I've run two Linux gaming machines on two GPU's, one bare-metal, one virtualized (yo dawg!).
It seems, even from the post above, that this is not greatly known stuff.
Game on Windows, customize on Linux. Or even better: update Windows in the background and have a perfectly working (yet busy) computer (☞゚ヮ゚)☞
It's not for the faint of the heart and requires some technical knowledge, but it's available on most current hardware and better than you expect. Look up Linus Tech Tips Linux gaming videos [1]. Or Level1Techs [2] or r/VFIO [3] for the gory technical details.
Seriously, most of your wishes describe some things I've at least saw working on Linux, at some point I've tried even to apply a Leap camera recognizing hand gestures. Unfortunately Leap has broke this at some point and it seems it didn't prioritize this functionality in the first place, and now Leap itself is dead.
And finally for moving the hand off the mouse to the keyboard I have two solutions:
- one is to start using the mouse left-handed (had a co-worker that did this),
- get yourself a split 60% keyboard (optionally with mouse emulation) [4], set the halves to align with the shoulders, place mouse anywhere (i have mine 15 cm from my right hand, measuring middle to middle).
[1] https://www.youtube.com/results?search_query=linus+tech+tips+linux+gaming
[2] https://www.youtube.com/results?search_query=level1techs+vfio
[3] https://www.reddit.com/r/VFIO/reddit
[4] Ultimate Hacking Keyboard ultimatehackingkeyboard.com (disclaimer owned, liked much), ErgoDox or derivatives (one of them was even in the video, misnamed as a shortcut keypad, just can't find the timestamp now).