I use Pangolin reverse proxy with OAuth (PocketID) for family access to services, along with CrowdSec, and for the Immich app access which needs to bypass auth login through the reverse proxy, I use ‘link share’ in Pangolin that gives me header tokens that can be entered in to the Immich app under Advanced settings.

I’ve been an Immich user for over 2 years now, so it’s been a journey for me to implement it to this standard.

Or as someone else suggests, try CloudFlare with something like Google Auth login. Just be aware that you are then exposing all your traffic to Cloudflare. I take that as a small sacrifice for simiplicity.