Maybe it's not the root cause, but it's very likely an issue due to tyre temperatures. Why? Because Tyre Surface Temperatures (I'll reference as TST) seem to have no impact to Tyre Carcass Temperatures (I'll call them TCT) - there's no "temperature transfer" or something like that.
A very easy test was loading up Miami in Wet (fixed) conditions. I went to practice, and my tyres overheated, as expected, however, I immediately noticed a somewhat weird pattern on the back straight before the final hairpin.
Wet surface had impact to TST - driving on wet surface (off the racing line) could cool down the TST down to maybe even 40 degrees Celsius. However, even when driving over wetter part of the track (not on the racing line), the TCT still kept climbing up since I was still driving fast, eventually to the point of severe overheating. I could drive over the "racing line" and since, it was slightly drier, TST would be a bit higher, but it wouldn't make any impact to TCT whatsoever, which to me makes no sense - why would the tyre carcass keep heating up while the surface was getting cooled off in the wet??
I think this "oversight" (at least in my opinion) might be what's causing some severe tyre temperature issues, even on dry tyres on some tracks. But it's mostly pronounced in wet conditions, of course. And of course, since AI always have perfect temperatures, they don't get impacted at all.
You missed the point of my argument. The player has been at a disadvantage against the AI regarding tyre temps since at least 2018, yet we've only just this year been at a disadvantage against them in the wet. Hence the issue most likely lies elsewhere as it doesn't make sense as the why it would suddenly start causing problems now when it didn't in the past.
I agree with your analysis that the tyre temperature model is simplistic and could do with an upgrade, but it's not likely to be the cause of the issue in question.
That's fair, though IIRC people have said last year that there were similar issues in F1 24 already... Though a lot less pronounced due to handling and AI and how everything worked overall. (I'll have to search the forum topics a bit, I might be wrong here, I won't lie)
Though the AI being OP in wet weather isn't entirely new situation either, I recall some of the older games (as you said, post 2018) had a similar issue where the AI would be a lot stronger than the player. Or, on the other end of the spectrum, they would be even weaker in the wet.
