I tried both voidauth and authelia and found that I really like that you can (actually must, as far as I’ve seen) configure authelias OIDC clients as configuration files. That fits a gitops style approach much better when paired with e.g. sealed secrets. It was a real pain to figure out that authelia configuration, hard agree on that… The official helm chart felt way too over-parametrized and is badly documented. The project website has a lot of basically-copy-paste configs for all kinds if self hosted software though.

Ingress controllers usually use the standard k8s services. In fact metal-lb allows workloads (like the nginx ingress controller) in the cluster to use services of type LoadBalancer, which is the default configuration. This results in an actual IP being made available to your ingress controller.

To get nginx ingress to use the external clients IP, you can configure the ingress controllers traffic policy. Using the helm chart, I used these values:

controller:
          service:
            # this has a bunch of downsides, but allows source-ip based access white/deny listing.
            externalTrafficPolicy: Local

For the ingress IP, I configured metal-lb to receive traffic on a static IP (using IP4AddressPool and L2Advertisement CRDs from metal-lb), which is then used for the port forwarding. I’ve never tested it because I only have a single worker node, but I expect the metal-lb controller will continue receiving traffic to that same static IP if a node goes down.

Gaming, as a basis for Valves Proton.

Having weak security on your operating system certainly isnt helping when there is some sort of exploit in a browser running on that system. The perfect operating system may not prevent issues inside your browser, but it may limit the damage these do. I feel like you suggest using Linux reduces security - why do you say that?

I would always recommend good old Debian for a mostly „it just works“ experience. You‘ll find debian packages for most if not all the things you mentioned. Alternatively you could go the steeper route and use an immutable OS like Fedora CoreOS or Fedora Silverblue for a more desktopy experience.

Hardware wise I‘ve been told the Intel NUC kits work wonders, or similarly specced boxes from Asia. You might get like 32GB RAM, a fairly recent CPU for <400€. Personally I‘m using a 12 year old Mac Mini until it dies, running debian.