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

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.