I mean... emby or jellyfin would be a better replacement for Plex.
But why not those? I bought a lifetime Plex Pass for $30 or something ages ago when the competition was garbage, so I already have a smoothly working setup for Plex. No reason to force my kids, their grandparents, etc, to a new interface for very little upside. Plex just works. I have tried the others and they're okay, but nothing compelling enough to force the change.