Recently I came across with an issue from a client that Customized objects are not available in sandboxes if that particular user has no Super permissions. Extension published as Dev not as PTE.
Therefore, after investigating the issue, we identified that we have created the AL permissions in the older way which is to generate permissions as XML file.
There’s a new command to generate a permission set as an AL object: al.generatePermissionSetForExtensionObjects.
It will create an AL file as GeneratedPermissions.al where all the permissions will be in AL language. It is easy to understand than in XML.
Afterwards it will create a permission set for the extension, and we can add that permission set to users.
Hope you find it useful.