What to do when you're overwhelmed by researching?

I struggled a lot to start writing my character when I needed to research the important stuff first. These include writing a culture that isn't the same as mine, needing to know what happened during the 20th century, including economy, politics, and pop culture, having to research how a lawyer works and how poc women get treated in those work environments, etc. When I make a list of what I need to research, it often gets big which is where I immediately become overwhelmed and end up procrastinating, never to finish researching or being able to write my character as a whole. I even overthink the possibility that I might miss something important.

I am aware of being a perfectionist who gives myself too many high expectations but I don't know if starting with something small is possible when I see everything as "too big" to start with.