I'm disappointed to hear of your disappointment. I have the core books for second edition but haven't dived deep. I certainly haven't had a chance to play. Some of the changes made me scratch my head but I haven't seen anything I disliked. Is it too rules heavy?
I would say it's probably a little more rules heavy than first edition, which sometimes made things annoying in the fact that sometimes when reading an ability, you have to understand the ability as well as understand the traits of the ability. Like summon spells were really confusing until you understand the like three different traits associated with that spell. But overall, that wasn't what prevented us from enjoying the game.
So for our group, it came down to combat. As some youtuber put it, Pathfinder 2e gives you the "illusion of choice". There are lots of options, plenty of feats for classes and skills. However, in the end, most of them are either too specific or are just subpar to other choices. So while in combat, you pretty much have several optimal choices. Basically, as I put it (and my group agreed with me) is that Pathfinder 2e reminded us of Dnd 4e... but without all the cool stuff. Which, if you've played 4e, they basically overbalanced everything. So level 3 felt very similar to level 13. Everything pretty much increases simultaneously. So your chance to hit increases, but their AC increases at the same rate. And there's no way to modify this, so it's hard to feel like you ever get "better". Except it's worse because it feels like even in an overbalanced system the enemies always had an advantage over the PCs.
This last weekend, group was level 12. Went up against 4 dudes that were each level 10. So the enemies hit okayish and the PCs actually hit decent since they were lower level (although their rolling was a little subpar, unfortunately), so there wasn't much question who was going to win in the end. The problem is that each of the enemies had 175hp. The PCs ended up focusing on two of them (because that's how the positioning ended up working). After 5 rounds, they finally dropped one enemy. The second was a little over half and the last two were untouched. The enemies were supposed to go. I just looked at them. They were mooks with a sword attack that applied poison and two different bomb attacks... but they were boring. Now, mooks don't need to be terribly exciting cause they're mooks... but they also aren't supposed to survive for more than 10 rounds. Even interesting attacks get stale when the boss lasts for 15 rounds because his AC is higher and he has 300hp.
So, I knew that combat was going to last another good 5-10 more rounds and I thought maybe I could modify them (reduce their hit points), but this was an ongoing problem and I didn't want to have to modify every single encounter for the rest of the Adventure Path (I shouldn't need to...) and I was like "Yeah, I'm done." The group looked at me, asked for clarification to ensure they understood and they all agreed we were done with Pathfinder 2e.
So granted that some enemies in PF2e did have some neat abilities and were fun to run as a DM, but sometimes they were boring and combat was just tedious. I know in PF1e fights that lasted longer than 5 rounds were rare, but now, any fight that lasted less than like 10 rounds were rare. Which sounds neat except that it's only because everything has so many hit points and it just becomes a slog when things are just trading blows.
We all tried to figure out what was going on. We searched forums and found people with similar complaints and the answers were always "You aren't doing correct stuff with your actions" or "your DM needs to modify things". But as I said, with the Illusion of Choice, we tried miscellaneous things and then fell back to what worked... except even that only helped a little, not ever enough to make the players feel like they had an advantage against the foes they were facing. And I feel like if the DM has to modify every single creature of every single encounter, that's not a time when "your DM needs to modify things" but is a flaw in the system.
So I'm not trying to complain, but rather to explain. We tried. We wanted to play through a single campaign 1-20 (and our group really enjoyed Agents of Edgewatch so we all wanted to finish it). But we tried and we tried and eventually we just couldn't do it anymore. We got to level 12. Multiple characters/iterations of characters. And we're done. Maybe we'll check out Pathfinder 3rd edition when it comes out. Maybe.