Is there a way to force Postman to prompt if you try to save something to a collection with any credentials, and allow prompt you to save without any credentials?
There should be a way to have environment variables, which are shared, but then the ability to have “local” variables that are not, or to specify that a collection should not be saved with credentials.
Not sure that I completely follow your use case here?
You could have a share environment file in a team Workspace that might have a set of variables - In your instance you can make use of the Current value which is use by only you have not shared/saved for anyone else using the environment.
You could also create a fork of the environment so that you have your own copy that doesn’t impact the rest of the team.
Anything else that’s not there or missing in term of functionality, you can raise that as a feature request on our Github tracker