Restore Deleted Channels by accessing ‘Channels’ listing
If you have accidentally deleted the channel, click ‘More’ option (visible as 3 horizontal dots) adjacent to it and select ‘Manage Teams’ as shown in the screenshot below.
Move to the right-pane and access the ‘Channels’ listing, and the channel will show under the ‘Deleted’ list.
Simply, check the ‘Restore’ button marked against it.
Confirm the restoration via the prompt-
The process of restoring the channel in Microsoft Teams can take up to 24 hours.
After waiting up to 24 hours, the channel should have been restored within the Microsoft Team.