You're mostly right but there are a few corrections.
-Osu will open with xquartz, it just takes a while.
-At around 6700 beat maps, the game bugs out and gets stuck in processing. (Seems to be due to Sierra, it wasn't there before)
-Xquartz osu seems to be locked at 60fps due to vsync (beamsync aka 'metal' on Sierra) which can no longer be disabled (on Sierra). (Although for some reason latency on 2015 osu seems to be lower-maybe vsync doesn't affect it? Idk, will do some more testing)
Basically, please fix osu on mac.
-Osu will open with xquartz, it just takes a while.
-At around 6700 beat maps, the game bugs out and gets stuck in processing. (Seems to be due to Sierra, it wasn't there before)
-Xquartz osu seems to be locked at 60fps due to vsync (beamsync aka 'metal' on Sierra) which can no longer be disabled (on Sierra). (Although for some reason latency on 2015 osu seems to be lower-maybe vsync doesn't affect it? Idk, will do some more testing)
Basically, please fix osu on mac.