u/Majestic_Status7169

In several of greep’s/bm music there’s this style of very theatrical writing/singing/composition he uses. For example: the defense, 27 questions (the corpse singing section), terra.

Where is he getting this style from? Is it musicals or something like that? It sounds very familiar like I’ve heard it before but I can’t place where/when.

Tl dr I used to play guitar in my teens for about 8 years. Got stuck because I never learned theory and just learned from ultimate guitar website.
Now I’m 30 and I’m learning trumpet and my dream would be to learn jazz improv. I’ve seen the wiki on this subreddit and my question is how far do I have to learn music theory before moving on to jazz improv. I’m aware this might take a decade, just looking for some guidance. Thanks in advance.

Edit: thank you all again for all your comments