You're operating by improv theater rules, where as soon as a character introduces a new idea, you say "yes, and" to it. But this theater troupe answers to your direction.
Being blocked on writing that one is obligated to do is something we don't usually think about the way we think about being blocked on creative projects.
The question underneath your question is: "Am I allowed as a commercial writer to do the thing I want to do as an artist?"
Lots of things happen that characters don't know about, or only hear about. That's part of life, and is perfectly fine to include in fiction. Instead of trying to fix it, have your characters react to it.
If you still want to write even after you let go of any feelings of being obligated to write, take some time to think about why. Are there ways to access those motivations and keep them in the front of your mind so you can gain some satisfaction and joy from them?
Let go of any inclination you have to identify with your work and interpret critiques of your work as critiques of you. Critiques of your work are critiques of your work. Your job is to use them to make your future work better.
You ask for the bones of plot, but it sounds like you already have those: start, middle, end, some drama. What you need are the muscles and tendons of plot, the pull and thrust and tension that turns a skeleton into something that moves and breathes.
I love semicolons; they're great. The issue is what you're doing with language and content that leads to the use of so many of them.
You can't thrive by only making art that feels safe and easy. But you also can't be brave all the time; you need rest, and play, and learning, and sustenance.
Nothing gets in your way more than a creative writing degree and a lot of practice doing other kinds of writing, both of which fill your head with all sorts of ideas about what writing should be like.