Non-comedy improv classes in Perth?

Hello. I am looking for improv classes that are not necessarily playful or comedy.

My goal is to improve my skills as a D&D game runner so that I can embody a range of characters with different motives in my fantasy world in a way that feels reactive and real and logical instead of portraying characters as sources of plot points.

I'm aware of Only The Human after a google/reddit search; I'm sure the skills I might learn there would be helpful, but I'm not really interested in the playful/dancy/silly/comedy aspect of improv classes.

Any recommendations that fit this criteria?

(Niche context for people familiar with mainstream D&D channels: Brennan Lee Mulligan is a god and I aspire to be like him)