Hi,
Few third-party platforms support Slack to Teams migrations, but not all platforms support Delta migration for Slack to Teams. Delta migration has been one of the difficult challenges for many organizations. Though they get a third-party tool that supports slack to Teams migration, it is difficult to get the same tool supporting the Delta migration.
You can look at this Article on Cloudfuze’s Slack to team Migration, which has started to Support Delta migration for Slack to Teams. Apart from this, you can go through their features which are supported by their platform.
Thanks