question

Please understand that PlayFab is usage-based pricing model, and if your title has launched, it is not specified on the limit amount of player accounts. If possible, tracking those bots account to see if there is any other behavior will be necessary to determine the priority.

My suggestions to check the login related PlayStream Events first to know how those accounts are created, if they were using the login methods that your client didn’t provide, set up API Policy to deny the corresponding APIs. Even though it won’t solve this issue completely, it can be a temporary solution.

The recommended workaround is to add tags for players when using your official clients to initialize player account. After the creation, you may add tags for those players who have input DisplayName in time (Set a timer on your client) or other necessary configuration (tags are added via Cloud Script/Azure function). You may also add a Segment to categorize the players who don’t own this tag via configuring “Tag” “is not” in the filter field. This segment will continue to refresh but there is delay. Then create a Scheduled Task and select “Run action on each player in a segment” with the ACTIONS “Delete Player”.