Sometimes, the most useful things may go unnoticed, this FLOW template can provide a list of new apps, flows, and connectors that have been introduced into your tenant within a configurable window. This is very useful when you are an admin and have to do some house keeping activities in the tenant.
Sharing an app with the user and, asking the user to run the app for one time will resolve this issue for most cases. I have had few instances where, new users with maker roles were unable to see the environment in the maker portal even after sharing the app. However, sharing a sample App with Co-owner permission resolved this issue.
The underlying structure of Model-Driven apps are totally different than Canvas apps. Model-Driven apps are created at environment level and owned by the organization so, if you need to give delete permission for model-driven apps, it should be given at the environment level. Means, this will give the permission to delete apps created by other users as well. This is the main reason why Model-Driven app delete permission is restricted to admin roles.