I understand where you are coming from, and I have been on the receiving end of very vague rejections as well (or being straight up ghosted of course). However

I understand where you are coming from, and I have been on the receiving end of very vague rejections as well (or being straight up ghosted of course). However, I don't think it's helpful to say "your work wasn't good". My natural inclination after hearing that is to say "ok, can you provide an example?" If they even have an example, you then jump into an analysis. They say you did x wrong, and you attempt to explain how x was influenced by y, or that actually you did x correctly just slowly and using a different methodology but ultimately the same result is achieved. I don't think I've ever met a corporate middle manager who has said "you know what, you're totally right. I'm going to cancel the firing process right now!"