I just this week did something similar for a line of business app API I'm migrating. I added code to the API to record all unique requests to a .http/.rest format file (natively supported in vlatest Visual Studio 22 and via extension in VS Code). I can then play those back manually or via automated integration tests that read the .http files. Yes, I'm hand-waving over authentication and downstream database and 3rd party APIs, but overall it's working well to quickly test against tons of production-like API calls.