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/
It's not fair to characterize jellyfin as being unable to scale, and it's just downright wrong to cast it as being built "for one single local user".
Jellyfin has great support for setups that include numerous users. The entire dashboard is basically designed around this concept of an admin keeping track of dozens upon dozens of users.
You seem like you have many reservations about specific functions in Jellyfin, but you were vague in explaining thrm - what specific things are you worried about?