I have never hit the thermal protection on the R5 as I always work within the stated limits. I was not aware of the limitation in 1080 120fps as I do not use this mode.
Thanks for testing this, now you know (along with the rest of use) to budget for a thermal limitation when shooting anything that is important using 1080 120fps.
I am confused to how this is "awful", but I do not claim to know your use cases for overheating the Camera.
Cheers