Text:
I consent to Plex to: (i) sell certain personal information (hashed emails, advertising identifiers) to third-parties for advertising and marketing purposes; and (ii) store and/or access certain personal information (advertising identifiers, IP address, content being watched) on my device(s) and share that information with Plex’s advertising partners. This data is used to deliver personalised ads and content, ad and content measurement, audience insights and product development. Your consent applies to all devices on which you have Plex installed. You can withdraw your consent at any time in Account Settings or using this page.
Soure: https://www.plex.tv/vendors/ (Might have to clear cache)
Can also read about the changes here: https://www.plex.tv/about/privacy-legal/
This is why I use Yunohost. It makes all of that just a "click buttons" affair. Then you can tell your Mom the same thing. Only the domain is yours so Jellyfin can't hold it over your head.
Does it work on a smart tv or roku or whatever?
Yeah they have apps on all the platforms.
All of these, plus more unofficial ones: https://jellyfin.org/docs/general/installation/