Try this guides on how to clear the broken filament on your AMS.
How To Clear Broken Filament Jam From A Bambu Lab AMS
How to Remove Filament Clogs from Bambu AMS
FROM Bambu Lab Wiki
How to remove the different PTFE tubes to help clear a broken or blocking filament
https://wiki.bambulab.com/en/x1/troubleshooting/broken-filament-anywhere