List Time Machine Backups
tmutil listbackups
Delete One Time Machine Backup
sudo tmutil delete "/Volumes/Time Machine Backups/Backups.backupdb/mbp/2020-01-26-021804"
Delete One Time Machine Backup (Big Sur and later)
sudo tmutil delete -d /Volumes/Time\ Machine\ Backups -t 2020-10-01-153636
Delete Multiple Time Machine Backups
sudo tmutil delete "/Volumes/Time Machine Backups/Backups.backupdb/mbp/2020-02-"*