Personally, I just installed another launcher for my shield (projectivy launcher) so I don’t have to deal with annoying advertising. You could also replace the stock OS with a foss android TV, but I haven’t tried it myself so I can’t tell you if it works well or not.
If it is in two different houses, why would you use a NAS as a client for jellyfin ? You’d better connect an android TV box like an nvidia shield and connect to the jellyfin.
Of course, the jellyfin instance should be accessible over the internet, either by setting up a reverse proxy or a VPN.
Can’t say anything for professional use, but debian is rock solid, always a strong choice for servers.
I would say, just check if voltage and and current are the same as your previous charger. If they are, you are OK. If they are lesser than before, you’ll charge slower. If they’re above, you’re gonna harm your battery.