I’ve tested the same arpeggiator plug-in on both my 2018 Mac mini (older version GP) and my brand new M4 pro Mac mini (latest GP).
same buffer settings etc on both machines (256 / 44.1k)
Old 2018 is triggering right on point (perfectly) whereas the current expensive Mac is about a few nanosecond late but enough to make it borderline unplayable live for pocket purposes, as you can imagine.
Same thing happens on the new Mac when I test my GP file that triggers vocal samples live. Just a tad bit late. Unusable. For that Im using AU sampler.
I would double check you are using your audio interface rather then internal sound card. (At least I would on a PC, I might be off that mark with regard to Mac’s).