Updated firmware to 1.93, can't connect.

The Relay Key entry should be 5th from the top in Communications. Which one doesn't work in Firefox? the phone, or the PC version? I'd have thought the PC one would be fine but I have to say I haven't tested it.

There will be some errors in the NPM install process I think, because it has an optional dependency on a windows package called winnus (which will fail on non-windows OS's).

Having Arch won't help, but if the espruino CLI software works then I don't see why the espruino-server doesn't - it's using exactly the same module and code.

When you start espruino-server after doing all that extra stuff and go to the 'connect' window, do you see noble starting scan now? If not, that'd still be a problem. You could look in /usr/lib/node_modules/espruino-web-ide/node_modules/ (or whatever your npm directory was) and see if noble was in there - if not you could copy it from /usr/lib/node_modules/espruino/node_modules/noble and see if that helps?