I heard in a Livestream that the CEO of a 3PP that made a lot of PF1 content complain that his business was pretty much blindsided by PF2. They weren't given any final version of the rules or heads-up of a change more than the general public. They couldn't update products in time. They were stuck making products for the "dead" PF1 product line.
That may have been a blunder but personally I'm -possibly- kind of glad for it.
There are small but extremely important changes between the PF2E playtest versus what the final book was. I do not know how late some of these changes occurred. But if they were very close to publication then I'm glad the choice was made to make them rather than hold them to let 3PP be OK. On the other hand if they were made months in advance then it was a blunder to not let 3PP's in on things.
Hard for me to decide on that though; lacking the information.
That said, Pathfinder Infinite shows they've not had problems with most 3PPs.
You can manually add things in with Pathbuilder. Hassle yeah, but it can be done. There are even a few 3PP things in there (they've popped up on me in making characters and I've had to remember to avoid them as they were from books neither I nor my GM had).
I'm still seeing more and more PF2E games being advertised on various discord groups as time goes on. I've not logged into my roll20 account in a few weeks so I can't say how that looks now as opposed to my last post here. I quit two PF2E games I was in on roll20 though - because that VTT is so bad with PF2E that it was just not fun to play there. For me it's Foundry or nothing. Not gaming is better than gaming with roll20.
As for the perception people have that PF2E is too hard or whatever... I feel way too many people watched a video by 'Taking20' a few years ago and never looked back. My experience and what I keep hearing from others currently playing it is very different than the experience of some rando D&D YouTuber from 2 years ago who had a vested interest in not losing his subscribers to another tRPG...