My S21 Ultra and my girlfriend's S21 Plus are not bright enough outdoors, in both sunny and cloudy weather.
Compared the maximum brightness on our friend's Iphone 13 Pro, our Galaxy S21 plus/ultra max brightness is looking 10 times dimmer. Resetting auto-brightness data does not help.
It hurts as I've been advocating for Samsung against Apple, however there doesn't seem to be a fix available for this issue. Great phone, however only indoors!! Hope somebody can help however not optimistic at all 😞