I've flown with Samsung phones and XCSoar for years, mostly the Note 4. I wanted to document a comparison of three inexpensive Samsung phone screens. Brightness levels at high, adaptive/automatic turned on. Taken just next full sunlight at noon.
Left to right: Note 4, A51-5G, S9.
For best comparison look at the upper right of each phone, which has less reflection from my white shirt. The Note 4 and S9 seem about the same, with the A51-5G brighter than the other two.