Sliding sync was recently implemented in Synapse itself, so as long as your Synapse is up to date there shouldnt be any more setup on the matrix side. Try checking the Synapse logs for any issues and/or the cloudflare tunnel configuration (I have no idea about what it does to traffic).
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.
The drive with the game files is mounted.
Where is it mounted? Try navigating to that mountpoint, not to the device itself.
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”.
Can confirm, very easy to setup clients. And since its not a VPN but a VLAN, you wont run into problems connecting between different clients.
This is pretty much open-source Hamachi.
I recently migrated from Element to Element X with first the proxy and now simplified sliding sync, and it feels way faster. Imho Element X is still very alpha software, so I wouldnt recommend it to the general population just yet (and I still occasionally have to open the old Element), but the speed is really noticeable on even a very small instance.