Why isn't courtship advice sought from men and women who have been in long term first time marriages rather than voiced modulated videos made by unmarried people with high body counts?

It also helps me explain things to normies.

OK, but then again, if the first step on that path is already not in the right direction, what's the end point?

Best to stay away from secular sources of advice. Even if it seems better than the lowest trash out there, the foundational premises about the human person are contrary to the Faith. Even if someone can break out of animalistic promiscuity, that "hoe math" realization only moves them to a cynical and utilitarian view. 

For starters: with traditional Catholics, there's no such thing as "dating", there's only courtship with the goal of sacramental marriage. Let the normies laugh at that if they want to. When they're ready to listen, you can try again. Some might prefer incrementalism in all things, but I'd say to stay true to the Truth and tell it like it is.

Try these videos from a Catholic YT channel instead: "The Price You Pay for a Modern Girl", also following for the young ladies: "Cake Eaters and the Early Feminization of Men". The content is from the 1920s and shows how little has really changed a century later.

https://youtu.be/TtY326729eo?si=5yZMCX4OlAkz-aBR

https://youtu.be/kTL-DWKHMNw?si=_rDn4hrQrq9z-7EJ