Let me say that I am not going to pretend to lecture you on airline hiring. For obvious reasons. First of which being you have been a 121 pilot, if not a 121 CA, longer than I have even had the idea in my head of wanting to do this airline thing for a living. With that out of the way, I just have a minor suggestion, which you have potentially considered already.
These people are airline management. They are HR people. Half of the people at the table or more, haven't flown an airplane in their lives. They don't care if you are telling the truth about some flying exploit or not. Unfortunately the system isn't, in this day and age, geared towards judging airmanship or a candidate's history thereof. What it is geared towards, as you certainly well know by now, is determining if you check enough of their boxes. I'm sure the boxes vary, but are still largely the same wherever you go. Something that you are saying is not what they are wanting to hear. This isn't the hill you want to die on, whatever it is. You want to make the bigger bucks, fly for a great destination airline, and retire comfortably (well, I can't speak for you, but that's what I want). You want to make it through the gatekeepers, so that you can be an awesome CA in a few years, and actually apply your decades of experience and expertise. The things that make you worth the money they will pay you. The reason young FO's will appreciate flying with you. Regardless of the throwaway day or 2 days you might spend in the interview, that mean absolutely nothing about you, or your values, or your worth. Tell the flying stories that are truthful. Be yourself, as it sounds like you are. But whether you think so or not, none of us can be 100% completely ourselves in that setting. Even us boring white cis guys. I don't have a flat top though. If I needed one of those for an interview, I'd go somewhere else
Just a couple thoughts. Don't give up. That is how they win.