You’re welcome! Depending on your needs to can also try alternatives to Postman, since that seems to be hard to get to work at the moment. Insomnia and Bruno come to mind. They are both in nixpkgs.
Edit: From reading the discussion on GitHub it seems someone created an overlay to pull in the older Postman file from archive.org … which is an idea I wouldn’t have had immediatly, but might work after all
So that would be the way to go if you really need Postman an nothing else.