But surprised by the post above:
"can expect to hear the heavy breathing of amorous couples from about 20-30m away as"
You are naked. But any kind of inappropriate activity is a big no no. Even staring at another person or something. Buddies of mine went to a sauna and there was even a famous actress in it. It is considered normal and egalitarian.
This being said, try Budapest. The scale of this bath will blow your mind: https://bathsbudapest.com/szechenyi-bath
I was blown away already before I realized there is even an outdoor area. It is BIG.
Showers within the sauna area are usually mixed. Showers within the dressing areas are not.
Saunas in public pools etc may have different arrangements.
https://www.wanderingermany.com/how-to-confidently-visit-a-n...
Tried to bring a US buddy of mine (non-mixed) into a Spa/hot bath/Sauna in Beijing. He got terribly scared of having to be naked and rejected. But it is a good place. And they have a good all you can eat buffet. Sweat. Eat a little. Rest. Repeat. You basically spent there the whole day.
With swimming clothes you soak everything then bring it back to the chilling pool and back to sauna.
Also imho nudity in sauna seems wierd first time but you quickly realize you can be covered all the time (with sheet) and that its not sexual at all because you are focusing on your body as does everybody else (heat stress).
Imho after few saunas everybody seems to shed this fear and even gain confidence and casuality about the nakedness part.
I think nudist pools are a lot wierder.