I've watched a few (4 or 5?) of the Galaxy Backgammon final streams from 2021, Mochy vs Dirk.

Wow.

What I'd say I've learned is that I tend to rush my moves. Watching a grand master trying two or three things out back and forward has slowed me down a bit. And I do tend to play a hyper pure game, rather than being smart about my positioning in the mid-board. Seeing Mochy building a wall with what would have been bad throws from a "pure" layout is a joy.

But everyone will learn differently I suppose. I might invest in a book, just because it's better than spending 6 hours in front of YouTube!