It’s can be exactly this with jellyfin as well. The minimal setup with no https is just that, run app, open port on router and port forward. If you want https it requires messing with certs manually or using a reverse proxy.

Plex can take care of the login for you by using their own servers to log you in. Non technical users will of course find this easier to use but now Plex has data on all your users and logins and possibly viewing habits as well. Proponents of self hosting and open source don’t like that aspect of Plex.

I personally think Plex will continue to add features that make it more attractive for someone like Netflix to buy. Those features are generally the opposite of what self hosted users actually want.

Plex has been around for a long time and has a decent amount of funding so they have better client apps. Jellyfin is catching up fast.

I’ve used my setup with web browsers, Android, iOS and it’s been very solid.