There should be a config file in ~/.config/MangoHud (you can check more details in the GitHub page https://github.com/flightlessmango/MangoHud#hud-configuration).
By adding frametime=0 to the config file, you should be able to remove the frametime measurement from the FPS display.
The vacuum cleaner. One cat gets really scared and freezes while the other starts hissing at the machine when I bring it out.