@nobodyinperson @vitriolix http://ssh-j.com/ looks like it is something similar as well (no endorsement, haven't tested it, just found it).

There is also a long list of things that might work for you here: https://github.com/anderspitman/awesome-tunneling?tab=readme-ov-file

@nobodyinperson @vitriolix How about https://zrok.io/ ?

Public reserved shares seem to be what you want: https://docs.zrok.io/docs/concepts/sharing-reserved/

I think it isn't accountless though.