I had a Plex server for years. It just got to the point where it wasn’t worth the time or effort to find a high quality rip. If I can’t find what I want on streaming service I just buy it or rent it on iTunes.

For movies, if you buy it from one of the major movies studios that participate in Movies Anywhere, it is automatically added to your library in Amazon Prime, whatever Google is using these days, Vudu etc.

But to your other points.

2. If you can find a high quality rip

3. All the streaming services work on iOS, Android, Roku, AppleTV, Windows and Macs and whatever Google device that Google decide not to abandon this week

4. I had a Plex server and 1000Mbps u/d and it still wasn’t as reliable when I was on a plane, outside the country etc

4. Plex lets you cache stuff locally for a plane or when you’re traveling. That’s usually what I do when I’m going somewhere. I did try streaming from my house to a hotel in India a decade ago… it technically worked, but I had to set the resolution so low that it wasn’t fun to watch. I assume that’s better now, but I just cache stuff before I leave now.