I am trying to connect from the NextCloud Android client (3.24.2) to NextCloud 25.0.4. The server is reverse proxied through CloudFlare (CF).
I can connect just fine using an internal address, by specifying the NextCloud port, but not via the CF routed endpoint on port 80, RP-ed to 8080. It just spins. I was able to do so prior to moving it to be reverse proxied.
A Reverse Proxy is not necessarily needed. AIO includes a reverse proxy which can handle the certificate stuff if you configure your public domain correctly and open port 443 to the outside.
It does support that by default. See the requirements above.
No it is not and will not be added as certain features require a valid certificate and https.