This is now resolved. What I had to do was set this in config.php
'overwriteprotocol' => 'https',
That allowed everything to work except LOCAL_IP:8080 from a PC browser, which wasn’t critical since the reverse proxy is on the same machine allowing local LAN access without having to use any public IP/DNS. Ironically, LOCAL_IP:8080 did still work from mobile.
Was also able to accomplish this in the docker-compose.yml with:
- OWNCLOUD_OVERWRITE_PROTOCOL=https
But, setting it in the .env didn’t to take effect.