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.