YA can never be too careful, you might be inside my network at this very moment and hiding the internal IP is my last line of defense! 😆

Not sure who downvoted lol but here’s proof

Your Roku should be trying to connect to the internal IP:8096 (Jellyfin port) of your arch device, not whatever your tailscale address is. I don’t personally use tailscale so if your setup blocks local access then you may need to solve that first