I finally, so far, have enough pieces in place that this seems to be usable. Time will tell if it lasts; I maybe already broke some stuff setting up Lutris, and it took me three goddamn distros to find one that would behave with Synergy, so this could all still implode terribly.
But for now, I have everything I need for work and play, ie. Synergy and FF14, and the transition has been tolerable enough.