I'm just now migrating my postman collections to .rest text files and the REST-client plugin for vscode (that name is both good and bad at the same time btw, it like marketing a new car and naming it "Car").
Grantet it does not do everything Postman does but I'm pretty happy so far. Environment variables and secrets stays in a workspace settings.json and the .rest files can be version controlled and shared.
This. My current hobby project[0] is basically something I started because I was frustrated with the inability to version control my tests in Postman alongside my API code. If it can't be committed to source control, then it's not really your code.
Now I can run all my tests FAST locally and set up a CI/CD pipeline in about 15 mins that will pick up and run them as well. At this point I'm not even sure a UI is necessary (maybe for the QA folks--maybe just an import from a postman collection will be enough for them, though).
Grantet it does not do everything Postman does but I'm pretty happy so far. Environment variables and secrets stays in a workspace settings.json and the .rest files can be version controlled and shared.
Always bet on text!