There we plenty of reasons to run behind a reverse proxy. I’m pretty sure that Discourse.org’s infrastructure runs behind HAproxy.
I use treafik and vcaddyserver, and have made nginx, HAproxy, and even apache work in the past (for a subfolder install query wordpress).
This is your problem. You need to enable b force_https and figure out why it’s breaking. Turning it off isn’t an option. You asked for free support and those who responded don’t have a solution for apache, so you’ll have to be the leader of the apache band.