I do write my own adventures. Some have been published or are in the process. Of course that was with 3.5, 5e, and OSR, never for PF2. In this particular case, I wanted to use Abomination Vaults as a way to learn the mechanics and to give the system a second chance after the bad experiences I had with Age of Ashes. Going about trying to write an adventure with a system as complex as PF2 with little actual play experience was something I wasn't keen on doing.You really might want to try designing your own adventures, I get the sense that it would actually be easier for you than these published materials, because the published materials demand you take the time to read them closely, internalize them, and then you have to still present it artfully to your players and improvise when they say or do things no book could expect. Whereas if you're at all like me, a couple of encounters (or better yet a list of appropriate enemy statblocks I took some quick notes of and the encounter tables on the back of the GM screen), and some improvised maps (a little harder over the internet but not intolerably so, easy with some wet erase markers and ye olde chessex maps) and some ideas and you can spin out something much more immersive and less constrained than a partial reading of the text. Its honestly way less time consuming, and really just requires a little know-how (less than any published module) and trusting yourself.
Edit: Which to preempt the obvious, was something that can be learned by a new GM, which I know from first hand experience (and for the same reason, serious issues running published content, i still get nervous when i volunteer for PFS or AL.)
The improvisational form of GMing is something I'm not at all comfortable doing in a new system, with players I don't know, and on a VTT to boot. I'm not even comfortable enough to run "from the book" - I have to put everything on there electronically to calculate attacks and damage, etc.