You’re saying two completely different incompatible things. In your last comment you said “You can just forward a port”. You can’t “just forward a port” or do any of the other things you suggested with Plex for free. Period.
The second thing you’re saying is using a VPN to trick Plex into thinking you’re local. You may be able to do that, but that’s entirely different from “just forwarding a port” or using a reverse proxy, or any of the other normal, easy ways to remotely stream over Jellyfin. It’s not only more work than sharing Jellyfin, but it’s also very limiting based on your users devices. For example, many people are streaming Plex, Emby, Jellyfin on RokuTVs. RokuTVs have an app for Jellyfin that can just connect directly, but it does not have a Tailscale client. So if you want to trick Plex into thinking they’re local, you’d now have to pay money to get them a new device, and then you’d have the configure the VPN on it, and troubleshoot that when it breaks. A lot of people are going to just opt for Jellyfin which is much easier and doesn’t require buying new hardware.
The point that you are entirely failing to grasp is that unless you want to pay up for Plex streaming, it is much simpler, with less limitations, to just switch to Jellyfin for remote streaming.
This is not the case at all. That’s not how routing, nor port forwarding works. This will work on Jellyfin, but if you do it on Plex without paying, this will be blocked. You are still fundamentally misunderstanding how literally all of this works. And it’s getting to the point where I’m wondering if you’re actually this confidently ignorant, or if you’re just a troll, given the only comments on your account are pro-Plex and anti-Jellyfin.
Users there would be shit out of luck with Plex too, because neither of those platforms support Tailscale or any other VPN. More clients support Jellyfin than VPN apps, so if you’re not paying for Plex, then Jellyfin is less limiting than Plex.
What you’ve failed to grasp is that Jellyfin is exactly as simple as I’ve made it out to be. You can forward a port, give your client an address to pop in, and remote streaming will work flawlessly, for free. You cannot do that same process with Plex for free. Only if you pay for it.