A nice summary, and one that's perfectly embodied in "Flourish". Can't use multiple in a round, or else unforeseen synergies might arise. I mean, unforeseen synergies is exactly why 3.5 has such a vigorous community despite being superceded twice by new editions from the original publisher. I'm being a bit facetious, of course, but PF2's design does seem to go out of its way to limit the combinatorics which drew me to TTRPGs in the first place.