Update 2: I inserted an European sim card, a few hours later I got the prompt where android asks if I want to replace Google and chrome with a different default search engine or browser (mandatory by law in Europe) and most important I finally got the prompt to update to Android 15 build AP3A.241005.015 which isn’t the Verizon “certified” one from 6 months ago

So at least I got this problem solved, I’m a bit sad that I can’t run lineageos (seller doesn’t give the super secret bootloader unlocking program that nobody ever saw and needs, but says I have to ship to him and pay an extra fee - I’m sure he’s just going to swap the phone with a T-Mobile one)