This is one of the most famous public saunas in Finland: https://www.kotiharjunsauna.fi/en

If the temperature there is not close to 120°C, we are kind of disappointed.

It's a multi-level sauna though, so it's "choose-your-own-temperature" (due to the hot air gradient), not everybody is there for the 120C experience.

This temperature cheating is one of the things I see very often in Gyms & public places: They announce with "fin sauna 90°", and then its only 80 or 82,so stealing some performance :-D