I have just recently started messing with Authentik. And I can confirm OIDC claims and whatnot are an absolute nightmare. I have some experience setting up SAML stuff from my work, but I only do that if our main guy is out and I always struggle with it there too.

Your setup sounds the most like what I am doing now, minus the DMZ. But all of my containers are rootless. I am running everything on TrueNAS right now.

I think I will lean more on Authentik, as the provisioning of users and giving them access to services through that is very easy. I will probably stick with Cloudflare for the time being, but I will look more into Pangolin.