Yeah, I've definitely gotten a huge amount of value out of plex lifetime. The problem with plex is the same as all commercial software. The profit motive is guaranteed to enshittify all of them eventually. Even companies that strike a good balance (e.g. Valve) are only a few deaths or bad decisions away from vultures and parasites taking over and destroying it for short term profit. I've personally experienced this over a dozen times in the last ~20 years, across most classes of software. That's why I refuse to pay for most closed software. All of plex's decisions over the last 5-10 years indicate it's only a matter of time before they completely destroy the value proposition. I also won't pay them a cent more, because of this trend.

The major problem with FOSS is the funding mechanisms available. Most require subscriptions too high to justify monthly when you want to donate to 10 projects, let alone 100; most don't even do yearly, or require some large minimum (like $50 or $100). I assume this is entirely because of the banking fees involved. Most are also built on top of other FOSS that nobody ever donates to. IMO the only long term solution is for legislation that forces all banking and payments for FOSS/charities to be zero fee – for all parties – plus the development of a FOSS payment platform where you can setup a single recurring sub that is split among as many projects as you choose, but also splits a sub-portion among all FOSS dependencies. The platform could even provide a script that users can run to periodically update their donation list. I don't want to donate to every FOSS dependency used in Jellyfin. I want all those dependencies to receive their cut, and for that to be the FOSS industry standard.

FYI I believe Jellyfin is cashed up and recommends donating elsewhere. I personally dropped $100 on VLC last year because I realised I'd never done that in 25 years of being a mainstay.

Wont be long before the terms change on what Plex considers "lifetime"

I think I bought it when it was first offered and it was $50 (maybe 2010ish?). While they are getting closer and closer to enshittification, trying to switch those over who access my Plex server would be a headache. I'll only do it if I have to, at this point. And it'll likely take them revoking the lifetime pass for me to do so.

Yes. They have a demo instance on their homepage with shows and movies you can test it out with

Yes, there are a few relevant features:

1. Playlist: Exactly what you think. You can create a playlist of specific episodes/films/songs in whatever order you want. And yes, you can just shuffle that playlist if you want.
2. Collection: Similar to a playlist, but more loosely structured and dynamic instead of a set list. Just an easier way to logically group together like items to make them easier to find. While this is not a hard-set list like a playlist, you can still shuffle it.
3. Plug-ins like ErsatzTV: Allows you to set up a television-like scheduling system for a playlist/collection. Instead of how you normally use a Jellyfin playlist by simply choosing what you want to watch on-demand, with ErsatzTV, your playlist is constantly playing in the background and you just "tune into" whatever is scheduled to be playing at the moment. Like the olden days of watching broadcast/cable/satellite television. But YOU are the one who created that programming schedule.

You may want to look into software such as ersatztv or disquetv

Starwars padme meme: with read-only access right?

That's not true, if you don't care about security you can open the port. I use a reverse proxy (caddy, super simple) which is somewhere in the middle security wise. Tailscale is more secure but a hassle on each client.