Here is Pocketbook App (epub copied by opds from Calibre Content Server) with the test epub on a TCL Nxtpaper 11 badly angled under the room light.
The phone sees more reflection than humans.
Same ancient Alcatel phone on automatic.
TCL Nxtpaper 11 (Nxtpaper 2.0 screen) is at 22% brightness.
(It's fine in full sunlight too).
It's also very much sharper and better colour in real life with no apparent glare.