I run my own DNS server at home, and have Tailscale installed on it also. I use this so when I am away from home, I can continue to use it via Tailscale and/or an exit node for full on VPN-like solution.

I can now, move Tailscale off that server, and put it on my Apple TV to use as my network for my DNS server when I am away from the house.

You can already do that officially... but maybe not region-locked sports

Definitely not region locked sports. My YT TV account is based on the other side of the country and I can't watch our local teams quite frequently. I've been using wireguard and a dedicated wifi network to tunnel through a fiber connection "back home" and it then thinks I am local and all works well. This is much cleaner with tailscale!

It's cheaper if everyone is in the "same household" (i.e. sharing the same public IP as main account)