An update allows Teams owners to archive Teams channels. This is an excellent way of keeping old channels online while removing them from open view. The PowerShell cmdlets have not yet caught up the archive channel option so they don’t report this status, but all good things come to those who wait and I’m sure that we will be able to report archived channels soon.
https://office365itpros.com/2024/03/05/archive-team-channels/
