Damn, I can rule out open hotspots, but wouldn’t know where to start checking for LTE (a Faraday cage comes to mind…)

Not if you never connect your smart TV to the internet to complete the setup and instead use it as a dumb display (I hope)

You can load your existing plex library into Jellyfin

Closest I could find to a non-reddit link

https://forum.jellyfin.org/t-solved-first-time-setup-slow-scanning-screen-load-times

Don’t do drugs. Ever.

If you are being pressured by your peers, change them. There are other peers out there who will value your decision.