Sorry for my somewhat unrelated comment (I unfortunately do not know of any explicitly safe servers :( ), but if anyone’s interested in making a server, consider using the following mod which adds pronoun tags to players. I was disappointed to see that no server that I tried was using it (or perhaps it just wasn’t advertised or presented in a GUI interface). (I haven’t tested it myself, but it seems like a feature every server should have)

https://content.luanti.org/packages/prestidigitator/pronouns/

I personally don’t play online servers for security reasons

It is all encrypted on the transport layer plus there is a chance that server side modding could exploit a client