This would be same in Germany and eastern european countries too. But it really depend on humidity. High humidity saunas don't have to be hot and get tough pretty quicky. 100c dry sauna is lot more manageable than 60c humid sauna (atleast to me).

Indeed, humidity matters a lot. Most our saunas here are löyly (in Finnish) saunas, so you get a rollercoaster of dry - humid - dry cycles. Once you get to 100+c and throw a good amount of water on the stones, it can get quite challenging to endure :)

Everybody has their personal preference of course. For me, the sweet spot seems to be a moderately humid sauna at 93c. At that point, the löyly is not too harsh yet but is still hot enough to make you feel alive :)

My steam room (at home) at 116F/47C is close to the upper limit of bearable for me. But that's a lot more humidity than even a humid sauna.