Pathfinder 1e was compatible with 3.5e in practice; my group based everything out of Pathfinder books and sprinkled 3.5e in occasionally.
2e’s four degrees of success/failure and the three action system codify the sorts of things 5e players always seem to want to squeeze into the D&D rules. The three action economy takes a few minutes to learn and then removes a lot of back and forth negotiation. Say a player wants to untangle a rope, swing on it past the chandelier, and kick a target in the head in one turn.
When I played 5e it often seemed to go like this: “Is freeing the rope from its anchor my action? I wanted to attack at the end. Is swinging my action, like a dash? Do I need to use my movement, or is the rope doing the moving, I feel like the rope would make me faster and I want to move after I land. I have multiple attacks, so after I drop the first one I’m going to move to the next enemy and attack. Wait, can I use my bonus action now?”
It’s not even necessarily that a DM is a killjoy, most of the time they let players do little extra stuff, it’s just that it kind of has to be discussed.
In Pathfinder, easy. That’s three actions. Grab, swing, attack. Next player’s turn.
2e is well made, and if you read tabletop systems for fun it’s worth knowing in passing, but it’s not going to inform how you play other systems the way Blades in the Dark or Call of Cthulhu might. Half the core book is conditions, traits, and spells.
I do encourage people interested in modern fantasy games to learn it to play it. For gamers who want crunch I much prefer it to 5e. Paizo’s #2 for a reason.