For some reason the cursor speed on menus is insanely slow.

Check out this command: scr_cursor_sensitivity

works, but feels wacky still

is there something like an external server browser? qTracker doesn't work properly, like it takes ages to make the servers show up for some reason.

Yea, the mouse support is not perfect. I usually still use the keybord to move around in the menus.
I do not know if there are any external server browsers around that still works. The ingame is ok i guess.