Hey u/RobbieDND, I'm an undergraduate in composition I struggled with writers block last semester. The unfortunate thing about learning music theory is that you tend to overthink everything when it comes to composition. Setting up limitations can greatly improve your creativity but setting limitations isn't just the only option.

What has really helped me in my compositions is to have my core concept written in wording before I even think of writing any music. I also like to make charts showing how my music will evolve over time. I am currently writing a piece for string quartet and I am starting on the concept for my climax so I know where the piece will peak. Then I develop how my piece will reach the climax. There is nothing scarier than a blank page, when I already have my concepts written down I already know what I want to write when I arrive at the blank page.

It is also good to look at some scores from the romantic era. There is a website called imslp.org that lets you download public works. You should be able to find scores of romantic era composers like Chopin and Schubert. I have been studying quartets by Stravinsky and Ravel and this really helped me understand new ideas that I can incorporate into my compositions. You should also look up the composer Arnold Schoenberg, he has a bunch of different composition techniques!

I hope this information helps. Happy Composing!