#Login with Global Admin id and update the email address below
Connect-SPOService -Url https://xxx-admin.sharepoint.com -credential {user}@xxx.com
# get a reference to the site collection where the site collection app catalog should be created
$site = Get-SPOSite https://xxx.sharepoint.com/sites/yyy/
# remove site collection app catalog
Remove-SPOSiteCollectionAppCatalog -Site $site
# Add site collection app catalog
Add-SPOSiteCollectionAppCatalog -Site $site
Note : Account used to create App Catalog Site Collection, must be Site Collection Administrators on both the tenant-level App Catalog and the target Site Collection