How to proceed when local repository is full?

My backups started failing a week ago as I ran out of space on the local (external) disk I’m backing up to. I hadn’t adjusted the retention policies to be aggressive enough.

Now that the device is full, I can’t seem to update the policy and run maintenance. What’s the best way to clear up enough space to get things working again?

Would prefer not to just start deleting random kopia directories until I get enough space.

Error when I update the policy:

ERROR error running maintenance: error running maintenance: error updating maintenance schedule: unable to complete PutBlobInPath:/mnt/wdportable/kopia.maintenance.f despite 10 retries, last error: cannot create temporary file: open /mnt/wdportable/kopia.maintenance.f.tmp.46fa37668a43db6a: no space left on device
ERROR error flushing writer: error flushing manifests: unable to write content: unable to create pending pack: unable to get session ID: unable to write session marker: unable to write session marker: s747573896c63567e8efa92d126d39704-se8169320286b9201116: unable to complete PutBlobInPath:/mnt/wdportable/s/747/573896c63567e8efa92d126d39704-se8169320286b9201116.f despite 10 retries, last error: cannot create temporary file: cannot create directory: unexpected error creating directory: mkdir /mnt/wdportable/s/747: no space left on device