The complaints about postman collection files being hostile to Git collaboration is valid, but I will just say: we managed to cobble together a reasonable workflow, persisting our postman collections in source control, by writing a utility that strips out all the guids that postman needlessly changes every time you do a collection export. We use Newman to run the collections in our CI pipelines, and as the main way to run tests locally.
It’s painful having to do an import/export of the collection from a file every time you want to modify the collection or debug a test, though, and the JSON files are still not entirely diffable/code reviewable even with the guids stripped. But it works - you can collaborate as a team with postman without using their cloud.
But the idea of switching to a tool that actually wants you to work that way is definitely tempting.