these are non foss options serveo.net localhost.run
there used to be a public instance of
https://github.com/fasmide/remotemoe but now its shutdown :( (Please come back)
there is https://ssh-j.com/ but it says "Users are encouraged to use it for SSH exposure only, to preserve end-to-end encryption. No public ports, only in-SSH connectivity"
So what are some other open source alternatives or any opinions?