DV is difficult to get working properly on PC, and last time I tried to set up an HTPC I ran into tons of remote control issues and it wasn't simple enough that I could just hand the remote over to a guest (or my spouse).
2019 Shield has plenty of issues sure, but it still seems like the best option for me, personally.
Agree about disable network on the TV itself.
SmartTube
You can connect Jellyfin to an SSO provider. It still needs work, and client support is lacking. Ideally I think it maybe should be built in rather than a plug-in (would definitely encourage more client support). But it exists.
https://github.com/9p4/jellyfin-plugin-sso
Feature request for oidc/sso:
https://features.jellyfin.org/posts/230/support-for-oidc-oauth-sso
As it stands, you could enable both the SSO and LDAP plugins, and let users do password resets entirely through your auth provider.
Basically, this is all stuff that comes with Plex out-of-the-box, but you sort of have to glue it together yourself with Jellyfin, and it's not yet in an ideal state. Plex is much much easier to configure. I wouldn't allow yourself to believe that Plex doing all this for you will make you totally secure through -- there's been multiple incidents with their auth, and IIRC the LastPass attacker pivoted from a weak Plex install. Just food for thought.
I think I remember being able to switch to anonymous user with it.