When I delete tags from Anki Desktop Mac on one device, and sync with Anki Desktop Mac on another device, the tags are not deleted from the second device (removal of a tag from a note does sync, removal of a tag from the tag list does not sync).
Each device maintains its own list of tags, based on what is present in the collection. That isn’t synced with the rest of the database. See Managing Files and Your Collection - Anki Docs .