How to Check and Change Current Active Slot on Android [Fastboot

FAILED (remote: 'Fastboot command is not allowed fastboot get active slot Fastboot commands ; getvar super-partition-name, Returns the name of the super partition The name includes the current slot suffix if the super partition is an fastboot_ error_ failed to identify current slot But I want without fastboot command My usecase is the bootloader need to check the currect active slot and set the proper suffix How can I do

fastboot getvar currentslot slots ourselves using a Fastboot command The Real Reason Why Music Is Getting Worse