If you're looking for Teams Shared Channels in the backup but can't find them, this article explains how they are managed.
How Shared Channels are stored
Each shared channel has its own dedicated SharePoint site. This ensures that access to shared channel files is restricted to only the members of that channel.
By default, these sites are created with a document library but can be upgraded to a full-featured site through the site management interface. Each site is located in the same geographic region as the parent team’s site and has a custom template ID ("TEAMCHANNEL#1") for easier management via PowerShell and Graph API.
Backup Location
Backups of Teams shared channels are stored in their respective SharePoint sites.
An example:
- Original team: Team1
- Shared channel: SharedChannel1
- Backup location: SharePoint site Team1-SharedChannel1, under the SharePoint list Shared Documents