It’s feasible as long as all the stuff you want to auth supports oauth, oidc, or saml. It might be a bit overkill for your use case, unless you have a bunch of services you didn’t mention. Keycloak has a bit of a learning curve, but works great once you get past that.
Media server client, pihole, emulation, programming or home automation project. You could even prop it up as a standalone web server and make some kinda creative thing.