I actually do both. Friends and family who are on the plex aren't on the tailscale network. But my personal clients are. I mean, not all of them. You obviously can't add a Roku stick or a smart TV to a tailscale network. Not trivially, of course. Maybe you could custom engineer a solution, but it might not be worth the effort. As I said in a previous comment, though, the best solution might be a dedicated cloud VM that serves as a reverse proxy into your network and which forwards traffic - either by having them both on the same tailnet and one just forwards traffic on specific ports, specifically plex's - or a reverse SSH tunnel. If I had to do it, I'd probably go the first route. Still, the network traffic costs might make doing that prohibitive. But it also might not. I haven't looked into it.