Here’s a relevant thread from a few months ago in regards to private vs. open testing:
And here’s a quote from Jason about it:
Edit: because we posted at the same time @Billy_Towers24: I’d think it’s generally better to receive the feedback in one place on the forums so the staff can see the results of your beta test, confirm that you did host one, and be able to understand from the feedback how to market your game, how well it was received, and etc.