Any advice on translating certain palette knife techniques into AR?

Applying, spreading, smearing translate readily, but when Bobs applies highlights, he uses a physical reality which exists on real canvas but not in AR: high and low spots on the paint to “catch” paint from the lightly-dragged knife.

Clearly I need a brush with a texture or thinner or loading I can vary; so far results are very, “meh.”

Maybe I need to completely forget about the tools Bob Ross uses, and embrace other techniques for applying color in the way he does it..

thank you for any tips on this!