I currently have the OnePlus 6T, which is barely visible in daylight. I'm looking for a phone (It doesn't need to be a new or flagship phone) that I can easily see and read in bright daylight.
I find the Samsung Galaxy S phones have the best and brightness displays.
Just yesterday I was in full sun, and after turning brightness up all the way, it(S9) was easy to see. Definitely brighter than my Pixel 3.
Good luck!
Welcome to Android Central! I agree with the above -- Samsung flagship phones are generally regarded as having some of the best and brightest displays. Earlier Pixels were often criticized for being a bit too dim, but the Pixel 7 line (and the Pixel Fold, as mustang7757 mentioned) is decent in the sun.