Your video is not loading for me, but I had the same issue with the filament runout sensor and had to disable it via gcode. Pretty sure in my case the lever for the limit switch got messed up, but I haven’t taken it apart to confirm yet.
See:
What should I do if the Touchscreens keeps showing “Filament Runout”? – Snapmaker
Unable to use commands in luban console - Snapmaker Artisan - Snapmaker: where creation happens
Regarding your second issue, the left nozzle does not move when switching to the right nozzle. At least on my machine it remains stationary while the right moves up and down.