I'm somewhat surprised so many people are surprised that 5800X is hot. It's a 105W TDP part (the max possible on stock on AM4), with a single chiplet. So unlike 5900X and 5950X the TDP is not split between two chiplets, unlike 5600X one chiplet is not limited to 65W TDP. With that added headroom 5800X is bound to be running at the border of the thermal envelope. If people expect/want it to run like the other three chips I'd suggest lowering PPT or use eco mode.
I want to add that the heat is inherent problem of the 7nm process, For example Zen3 in eco mode (65W TDP) will still boost to 5+ GHz and cause temperature spikes. Eco mode is targeting PPT, whereas per core temp could still spike due to a single core boosting to oblivion.
On the bright side, you dont lose ST performance in eco mode, and if the fan noise is bothering you, you can alter the fan speed profile because according to AMD Zen3 should be perfectly fine working around 90 degrees celsius daily.
5800X is particularly very boosty in ST, but since it is not as highly binned as 5950X it uses more voltage to reach the higher speeds and therefore cause higher temperature spikes.
During all core loads, surprise, the temperature actually does not spike. This is my observation so far.
But Zen3 has a much better temperature curve than Zen2 for sure.