Filevault stuck!

I was using Filevault for encrypting my external hard drive with Time Machine. Upon wanting to decrypt to then manage some files, Filevault got stuck and now I cannot turn it off. I have tried everything from working in terminal to turn off Filevault to erasing and re-formatting the external hard drive that had all my Time Machine backups. Upon mounting the re-formatting external hard drive and trying to run Time Machine, it said backup could not be done because of Filevault. I am not sure there are any more options for me other than to wipe my iMac and install Big Sur fresh and lose all of my information that is not stored on iCloud.