I've always tried to enthusiastically "sit through" such sessions but unless the field is really really close to my own, I don't understand anything.

Like their whole literature or notations feels alien language to me.

In one of such cases, I wanted to know about "differentiable programming languages" which was posted here recently. I watched this seminar (https://www.youtube.com/watch?v=x1-YOWa0vJU) but I didn't understand anything and lost all my confidence in what I knew.

(Note that I searched the presenter, he is very much respected in his field. I just provided that clip as an example. It's not just this, as I said, I feel the same in 90% of similar topics)