I used to make my thesis way too broad, basically trying to squeeze the entire essay into one sentence. It usually sounded impressive but gave me no clear direction when I started writing. What helped was treating the thesis as the actual argument rather than a summary of the topic. I also found this guide useful because it explains how specificity and an arguable position make a thesis stronger: https://essaypay.com/blog/how-to-write-a-good-thesis-statement/. Since then, I usually write a rough version first and tighten it after I know what my evidence is actually saying.