technicalitch
When I first used the Redmi 15 5G for an hour or two, a while back, I immediately set the display to a fixed 60hz refresh rate, and enabled the eye comfort/paper mode. I managed to use it for an hour or so without much discomfort or issue.
The display felt noticeably sharper that the Redmi 14C, and both had elements of the toxic backlight issue. But overall, it didn't cause immediate eye strain.
Maybe there is also a display lottery issue with the Redmi 15 5G, or maybe strain symptoms would have materialised the longer I would have used the handset.
I have not had a chance to use the Moto G57 power. It hasn't received a national release in the UK/amazon, and it is only available to purchase directly from Motorola UK. But from my past experience with recent Motorola handsets, like the G54, G55, G75, none of them were comfortable, with the G54 and G75 being the worst (immediate discomfort).
In terms of recent handsets, it may be worth trying the Realme 14x if you can. It's had good feedback from users (myself included). I used it for many months, trouble free. Only noticeable issues for me were to do with the battery life and performance. The Dimensity 6300 isn't a great chipset.