Deactivate HTTPS in Nextcloud

I set up a Nextcloud-container, but I can’t get it working with HTTP-only.
I use a reverse proxy which handles my SSL-encryption, and I can’t get it to work with self-signed certificates.

Unfortunately it’s not an option for our container unless you manually edit the nginx instance within nextcloud.

Any good reverse proxy solution should work with the self signed cert. We know and have tested it works with nginx and traefik.

Could you tell me what I have to edit?
I already tried the nginx configs, but then I couldn’t reach the page, or I get “Too many redirects”