AFAIK there is no deletion mechanism in AB. At least public one. But you can resubmit correct data without deleting wrong data. One records can have many AB data submissions, and the same AB data submission can be submit for many records.
IDK how it work in Picard, but old acousticbrainz-client has local mechanism to prevent second submission of the same file. This mechanism can me bypassed by move file to another directory or by deleting local abzsubmit .db file stored somewhere in user directory
Thanks for the tip. I was able to submit new data and it was accepted but the old incorrect data still shows up by default since it was the first submission. You can check for yourself by comparing the lengths in the submission metadata to the actual recordings on MB. So it’s not the best solution IMO.