Isn't this only triggered when user use Gemini (and the google assistant before). To use something like circle to search. I'm rather sure this already exists before AI craze
Yes you can do the same thing for Jellyfin. I use Synology ddns and setup subdomain in reverse proxy to jellyfin port.
For tailscale, I previously use this but needs to add the jellyfin port after the tailscale IP.
Enable quick share to receive from everyone (if using different google account) in receiver side, this should be there in quick setting from swipe down (if not there, maybe it's hidden, try to find it in edit setting). And then on sender when sharing, just use quick share. It will then show nearest devices.
Afaik, it will use wifi to transfer the file, so it's much faster than simple Bluetooth
https://futurism.com/artificial-intelligence/microsoft-satya-nadella-ai-slop