Some FSA's I've ridden were "ughhh clank!" for the upshift & a "hrmmmmm swoop clunk!" for its downshift [2x system] & almost all the Shimano stuff was predictable with some minor shifting grunt. Once on the gear, both performed fine.

Would I swap out a square to something else if there's no obvious BB issue? Not in the current times, but would have 3 years ago quicker than a squirrel burying a nut.