I used to go to a UU. At the time they were very diverse in belief. Some UU were atheist and others were almost like any other church. I went so I would not feel so alone in my approach to reason and religions. I quit when the UUs around me became increasingly religious. The only way you can know is to visit the UU near you.
Most UU are highly liberal. There probably are some conservatives among them, but not a lot.
This is from my personal, and remote experience. I hope someone can give you more recent and relevant info.
My atheist family has been part of a UU church in Seattle for over 15 years. I teach Sunday school and am a coming-of-age mentor. It used to freak me out to go to a "church," but I got into it once my daughter talked me into teaching Sunday school. My wife picked the most intellectual and least woo-woo congregation in the area. When my wife got really sick and passed away, it sure was great to be part of an intentional community.
<another thumb up>
I know an atheist who's quite comfortable in her UU church in the greater Boston area. Your mileage may vary.
Hmmm, so they study the bible. Might be a good way to keep up with biblical nonsense and getting to know people in the 'hood, while maintaining spiritual distance. Interesting!
By all means go for it and see what they're all about.
I'm not for any "church" at all once I opened my eyes, UUA might be the most liberal. I understand that some are openly atheist.
There are also Unitarians who don't want to be part of a "church," so they call their congregations "fellowships."