That's still crazy hot, I know intel cpus are rated for 100c, but you're bumping right up against that.
I think it's fair to say that there is almost certainly no difference in thermals compared to the 2018 model (more cores, same arch and TDP, same chassis). Somewhere between 12 - 20% improvement in most sustained load tasks compared to the 2018 2.6 base (I think Cinebench is a pretty good test of this), but probably near the lower end of this spectrum on average.
It's all quite reasonable and predictable in the end, and not at all the massive leap forward that the Apple tech site headlines are shouting from the rooftops. The chip and chassis design still resembles a supercar commuting in rush hour.
Worth the money for some people but not for me. I'm sure the minority of MBP users who really need their speed will won't bat an eyelid before upgrading, 12 - 20% is still nothing to scoff at if you're maxing out your cores most of the day.