Can anyone help with external access via reverse proxy?

Nextcloud version (eg, 29.0.5): 29.0.4
Operating system and version (eg, Ubuntu 24.04): docker via unraid
Apache or nginx version (eg, Apache 2.4.25): replace me
PHP version (eg, 8.3): replace me

The issue you are facing:
I was happily using reverse proxy with nextcloud for years but after an update I can no longer get it working and everything I’ve tried to get it working fails.