The problem there is that, if Paizo was just porting over material from PF1 into Pathfinder 2E, they'd have reproduced the copyright listings from the OGL listing for whatever PF1 products they so used in the relevant PF2 books. But they didn't; here's the PF1 Core Rulebook Section 15:
And here's the listing of the PF2 Core Rulebook Section 15:
As you can see, there's no PF1 material listed in the latter.
Now, to be fair, I've seen some people put forward that you can omit Section 15 copyright references to your own works in a subsequent OGL book that you publish, under the idea that in that case you're both the person committing the infraction as well as the "wronged" party; what are you going to do, sue yourself? But in this case, the PF1 Core Rulebook Section 15 references works by other people, such as the
Book of Experimental Might and the
Tome of Horrors, so that wouldn't fly if they said they were using PF1 material to make PF2.