You might have better luck with Jellyfin, than Plex. Plex uses online authentication tools, which is used for not just user, but server management. In contrast, Jellyfin can be ran completely locally.

Now one thing to note is that neither solution will properly detect your media files properly. You’d need to manually input file details. Usually these servers would do a quick online search, to detect that your movie is what it is. You could import this data, but you’d need an internet connection to acquire it. If you do not mind all that busy work, then you should be fine.

Now the remote… honestly, no idea. I’m pretty sure Android TV has a button remapper app, which might help… Do modern Chromecasts use Android TV? I haven’t used them since their second generation. Best do some research yourself, or wait for another reply.

If only one device is involved, Kodi is still pretty solid I think.

To simplify my setup using Google TV, I installed a custom launcher and set that as the default one. This removed the horrible home screen and now I just see Jellyfin when the TV turns on. From there, it's a Netflix like experience. Also, the TV remote is able to control the volume of the AVR, so it's a single remote experience. I tried the button remapping route, but abandoned that. The custom launcher is the way to go.

A long time ago I used to use a PC with a remote and Kodi and it was nice, but you'll still need two remotes to get it all working.

Jellyfin on a debian box (more resiliant en no forced updates bs)

Then maybe setup the Arr suite, so they can request any movie on Jellyseerr and it will get downloaded automagically and added to the Jellyfin library

And they just interract with the Jellyfin chromecast player

The best way (but not the cheapest) to emulate an android TV with Netflix is to buy a Chromecast for the existing TV and then access a service with that Dell Optiplex you were thinking of.

Then you can do this:

Jellyfin on TrueNAS. Super easy to install and administrate and will not break or complain like windows without prolonged internet access. Jellyfin will have 0 problems without internet where Plex will eventually have some authentication issues because they are closed down and proprietary.

Then you would just install the jellyfin app on the Chromecast (or any Android TV box), add a few accounts for whoever wants a seperate watch list, and off you go: Netflix without Netflix.

How you get content is still a hole though. Workflow of ripping Blu-Ray is very different than torrenting. For the latter you will have a harder time without internet, but setting up radarr/sonarr/prowlarr/bazarr is worth it.

I use a Chromecast with Google TV, but any Google TV device would work. Run Plex on my computer and it just works.

Never thought about the idea of an remote for a pc. Nice idea! Definitly more free than the usual options like shield, fire tv and so on.

I guess the way you suggested would be really nice :D

Are you in the US? If you are you could pickup a onn TV box. It requires a google account but you can install the Jellyfin app.