I've always been allergic to spell casters (the strategy behind the best use of spell slots just never clicked for me - which is extra painful because it seems like if should be simple, but I consistently manage to botch it), going back to when i picked this all up in the 3.0e days.

I think that's caused me to not really engage with the spell casting side of spell casters in PF2e. I remember in 3.5, we banned Mystics because spontaneous divine spell casting was broken, so maybe I just need to run one to see if work.