The setting for "Age Range for Apps" is under Settings->tap your apple account at the top->Personal Information->Age Range for Apps.

After some trial and error, I added the Declared Age Framework Capability under my main target in my main project in my workspace which created another entitlements file specifically for this project. At first, it did not work with our generic entitlements file which was also under that project, even though that file appears to be referenced from the main project file as well. The difference seems to be that CODE_SIGN_ENTITLEMENTS is set to the new MainProjectName.entitlements file under Build Settings for the main target in our main project.

Same here. Our macOS accounts are not admin. Every time I try to do something that needs admin a window pops up asking for justification. But I see no such alert when Predictive Code Completion tries to install.