Hey @postman-paul540. We are actually in the process of introducing version control within postman, which is effectively targeted towards solving use cases like the ones you mention. We have a public RFC that goes in more detail about it.
Basically, you would be able to fork a collection and create a copy of it in your personal workspace to make changes that are not synced to your team members. Once you’re done making changes, you would be able to merge your forked collection to the original one, which would then be synced to all the team members.
Feel free to add your use cases in the RFC to help us improve the experience.