Im not sure how difficult it is to setup a Tailscale client, honestly.
The Zerotier setup is just installing and joining a network by an id. The Windows version has a bit of a GUI, where you have to right-click on a status bar icon, click Join network, paste in the id and join. The Linux version of the client has a cli, which is imho even better, as you can just send them a whole command to copy into the terminal.
I admin a Zerotier network for a bunch of kids that wanna play Minecraft, and they havent had many problems setting up.
There is a bunch of information on self-hosting the whole system, but Ive honestly never tried any of that. It was just nice that this was “just the open-source LogMeIn Hamachi with a superior implementation of everything”.
What is the format of these videos? Im afraid you wont get much compression out of conventional file compressors, as video files are usually already compressed to the point where you would have to reencode them to get a smaller file.