"You actually can't override a few of the events such as Control-W"
I definitely did overwrite it in my app, but I just checked and remembered, that you also have to be in full screen mode.
WebRTC data channels would be ideal, so that clients can connect directly to servers (or at least regional proxies) in a UDP-like way. Vanilla minetest would need to include an WebRTC endpoint for this to become universally available. There are lots of details that would need to be worked out.
Although the support isn't amazing [1], I believe you can capture C-w and friends [2].
[1]: https://caniuse.com/mdn-api_keyboard
[2]: https://developer.mozilla.org/en-US/docs/Web/API/Keyboard_AP...
This port uses a proxy for networking, as the main game uses UDP-based networking [2]. Perhaps it would be possible to upstream basic WebSocket/WebRTC packet-wrapping support to the servers in the main Minetest project?
I am also curious about the storage issues.
[1]: https://source.chromium.org/chromium/chromium/src/+/main:chr...
[2]: https://dev.minetest.net/Engine/Network_Protocol