I think 4e was a much less complicated system. The entirety of PF2 to me feels like the grapple rules from 3.x. The exception based design is like "sometimes a check works like this, sometimes that." Case in point is the disarm/trip/shove example above. Sometimes multiple attacks put their penalties on each attack, sometimes it doesn't (depending on feats, monster abilities, class abilities). Sometimes those penalties change due to weapon factors (agile, sweeping, etc). Nearly every spell has different effects based on failure, critical failure, critical success, regular success. Or if you upcast it, which is sometimes automatic and sometimes not. And when it is upcast, your character level isn't the spell level. And then all those effects can be different based on the number of casting actions you use.
Nearly every condition has four different ranks. There are dozens of different conditions.
Some characters get reactions, some don't. Some get different ones. You have to track damage to shields and other equipment, using Hardness in every combat and every attack. So most warrior combatants are tracking at least two HP lists.
Initiative is rolled in various ways, kept separately for every single opponent.
I can continue if you'd like.