They're all visible under sunlight if you hold your hand over it to shade it.
Aside from that, it depends mostly on the angle of the light and glare. There are no OLED displays and
very few LCD displays that really look good under direct, full sunlight.
I got my wife one of these Amazfit watches when her Fitbit (I mistyped it as fibtit soooo many times just now) Charge 5 got flaky and would not charge or come on half the time (just like her Charge 3 did after a couple of years).
View: https://www.amazon.com/Amazfit-Fitness-Tracker-Monitoring-Resistant/dp/B09Z6CRHJ6
So far (4 months) it has been great. Works as you would expect but it is paired with an Android phone so I don't know if that will make a difference. Basically all she wanted was something that can show the time and date, track her steps, and do basic notifications. No need for any crazy invasive other tracking like heartrate, pulse oximeter, blood pressure, etc. on some of the more fancy ones.
The screen is decently bright but in direct sunlight on a bright day, you need to shade it a bit to see it really well.
I figure that if they are all going to likely crap out after a couple of years, we might as well go with a $50 one instead of $150 since they mostly do the same thing and look about the same.