Infuse is a nice app but note that it does not use the media server's transcoding service, so it can work poorly trying to stream remotely, while Jellyfin's transcoding-aware web client works better. The Jellyfin app for Apple TV was pretty unusable last time I tried it, though.

This sort of underscores the ancestor's complaint: It's not exactly dead simple to set up and understand, the community recommends third-party apps that have only partial support, etc.