we are trying to migrate from TFS to Azure Devops and as part of the migration want to migrate work items. I had tried using VSTS-work-item-migrator and vsts-sync-migration tool for migration but couldn't be succesfull in doing that as there are some customized WIT's in current TFS. Can anyone suggest what would be best approach to do migrate without any data loss.
Note: We don't want to use import database approach.