Hey guys, sharing this in all Android 12 performance-related threads I find in case it helps anybody else.
I found a solution that works but it's not good.
Led by some users here in the Zentalk forums, I downgraded from Android 12 (Version WW-31.0810.1226.91) to Android 11 with the 2022/07/13 firmware (target Image Version: WW-18.0840.2202.231) and using my custom tuning, the cooler attached, and x-mode+ enabled, God of War 2 finally manages to stay at a constant 60 fps.
There's a clearly marked difference in the thermal limit between A12 and A11. In A11 the CPU gets to 50ªC and in A12 it never got past 45ªC.
While doing so A11 does use both the high-performance prime and big cores and manages to keep them at higher frequencies for longer.
Without the cooler I get dips to 50-55fps (much better than the 40s I was getting in A12) and with the cooler fps is pretty much constant 60 and temps stay at ~32ªC in my current weather of about ~10ªC.
Leaving this here for others that may come upon this. Feels like a shame that this much effort should be put on the user to get max performance out of your device. Happily available to provide more information to help fix this issue.