I will say I will not buy a system that uses +1 per level with bounded accuracy. I was not a fan of it in the systems that pre-date PF2. So currently it is looking like I may only use PF2 as a place to pillage for house rules.
Flat(ish) Math with bounded accuracy has some advantages. (AKA dice is god)
1) It leaves more of the monster manual usable as levels go by. As even if all the monster represents is a theoretical threat that is often enough when made part of a mixed encounter.
2) Simple math, I don't know why it takes Dave so long to add 21 to a dice roll but it does. So simpler math can be quicker.
3) Fairly static DC's make GMing easier to get familiarity with.
It has some issues in that:
1) It can feel mechanically boring.
2) It can have narrative issues, the uncharismatic half ork barbarian winning the battle of the bands against the half-elf bard is interesting once. After the third time the half elf player was not amused.
3) Everyone rolls for everything as its mostly up-to the dice which can be slow.
Unbounded Math of the PF1 kind did also give me some advantages.
1) Player agency if they wanted to be good at something, they could be to the point the math breaks and spins off into the setting sun. Took me a while as a GM to be happy with this but these days its yes your character is absurdly good at this you succeed.
2) One resolution system, the difference between an epic jump and a normal one, the DC.
3) Can help characters feel different. Wizard verse fighter etc.
Downsides are
1) Math is someone suspect and can take time for the player to resolve.
2) Saves can get to the state where it becomes fairly binary.
3) Can encourage "roll-play" over role-play.
The PF2 system comes with only downsides for me and my GMing.
1) Monsters become obsolete as per PF1
2) Math is still going to take Dave god knows how long to resolve.
3) Its mechanically dissonant from expected results. (The whom is better at first aid example, the new paramedic just out of school or nearing retirement John from accounting who has never seen a bandage before(*)...) The patch for this is feat gates but lets be honest gates have never been particularity popular.
4) Resolution complexity, instead of the DC, it's now DC plus when-either or not it should be trained only, expert only etc...
5) You can end up on a treadmill that defeats all sense of progress. If at level one I need a 11 to succeed at a task and by level 10 I still need an 11 it going to feel quite similar, regardless of the numbers involved.
(*) Yes you can "sort of" fix this issue by ensuring that all NPC's in a world don't exceed level 4. However from what I read of adventure paths this is not the case and it is also quite limiting for GMing to only have such worlds.
Also the its fantasy who cares argument misses the point it is easier to make the fantastical magical if the base system at least ensure the narrative expected result is the default. The John from accounting saved the casualty because of the magic beans he ate is interesting in a way. He saved the casualty because of his 30 years reading excel documents is weird.
(The to level he must have seen combat is only true in a world without quest exp. He could have just completed a lot of accounting quests. A kill only XP world is fundamentally different and changes the very social structure.)