I've made the mistake in the last year that I worked on promising ideas but those ideas were not actually what I WANTED to work on. When you really want to work on something, you have a strong feeling about that. Don't accept mediocre projects where you lack motivation. Wait for an opportunity to work on something you want. I think this strong feeling is the best case scenario, but of course it's all on a spectrum: Some things you want to work on more, some things you also want to work on, but you don't feel as strong about it. For me it seems easier to choose a project you feel really strongly about. But this is not a one-size-fits-all decision. Decide for yourself what you're going to work on, but always remember that it's possible to get a very strong and positive feeling about a project.
For about 10 days, I had the chance to work on the project www.audiodiary.ai. From the moment where I discovered the project, I was really motivated to work on it. I finally found a fit! A project that I really wanted to work on. While working on it, I recognized that I had a much higher output than usually. And I had so many ideas sourrounding the project. All of this had to do with really wanting to work on it. Unfortunately the founder decided in the end, that he wants to pursue this project as a solo founder after all. But that's besides the point. I learned that there ARE projects I love.