IIRC the acceleration curves supported by Sway are the same as libinput, at least that's how I understood the poor pieces of Dokumentation I found [1]. I don't think think libinput supports offsets and upper limits, so it's not really useful for gaming.
I'd recommend going with leetmouse, which does work well (altough I don't use it anymore).
leetmouse by systemofapwne is more up to date and includes the PR of N-R-K [2].