After allowing administrator to recover deleted Teams, Microsoft Teams has been updated and now allows you (and I mean end-user here) to recover deleted Teams channel for up to 21 days after the channel has been deleted.
To recover a channel, the Teams owner needs to go to the Teams settings (Manage Team)
Then you go to the Channels tab and open the Deleted group to select the channel to recover and click on Restore
Finally confirm the recovery
Et voilà your deleted channel is recovered