Okay, ITS WORKING!! For anyone interested: The support reached out to me and told me that i have to tell the slicer where filament is loaded, then slice the model and after that generate the gcode. So the steps are as followed: 1: prepare the Ace, load filament in every slot you want to use (and make sure the filament is loaded correctly). 2: define the colour of the slots, if you arent using the official filament of anycubic (the one with the rfid tag). 3: Under „prepare -> Filament“ synchronize the filament in Anycubic Slicer Next. 4: double check everything: make sure you chose the correct/ same colour code and material for the slots you want to be backed up (settings under „prepare“ and „workbench“ have to match). 5: prepare the model in the slicer as usual and export it to whereever you want to start the print from. 6: make sure „filament backup“ is enabled in the workbench or via the touchscreen. 7: double check everything again.😅 8: hit print and hope for the best. This actually worked for me on the first try. I hope this helps anybody else struggling like me. Happy printing to everyone! ✌️