My players have become fond of an NPC and are trying to train them up as a sort of member of the party.

So far I’ve been kinda fudging their stats, but I’d like to come up with something more concrete. I’ve got the D&D 5e book Tasha’s Cauldron of Everything, but unfortunately that’s a super slim set of rules that mostly focuses on “at this level, they get this specific ability”, so doesn’t provide a lot of help in translating to Pathfinder.

Does anyone know some good variant or homebrew rules for giving the party a Sidekick in PF2? Or alternatively, have any advice?