Free ones are less common now (no-ip went paid.) Afraiddns is still free but requires regular account logins.

If anyone goes with finamp, sign up for the test version as it’s UI is significantly better than stable.

You need the web site to use a certificate from the same root authority as your client certificate. Otherwise browsers won’t present the certificate to the server. That means either warnings on connect or adding the root cert.

I do think if you are doing it with them in person it is doable to add it.

I recently did exactly this. Only works with the web UI, no apps support it, but working well and those without the cert just get a 400 error. Not sure if non technical tbh, since you will get warnings when adding your root certificates to any device, and that might scare some who don’t understand what it does.

Also set it up through wireguard, so can punch out of double NAT.