Rekordbox Agent Mac Big Sur Question

I recently got a Time machine disk full error on one of my Macs I have an external drive with two partitions I wanted to erase the Time machine data clean it out and resize the partitions, I was able to erase on partition but the second partition will not let me erase the volume as I get the following error see the image plz below. What do I do here as I'm currently not backing any data or music right now and don't want to be without backups for too long. Any help?