Iphone XR keyboard “a” letter not working… maybe ‘w’ too

Hi-maybe you can help me.. i’m dealing with my mom’s iPhone XR… no matter what app she uses, be it Safari, Notes, Facebook, Mail, and she has to use the onscreen keyboard for typing, most of the letters work, except for “a” and “w”… i’ve tried doing the following: hard reset of the iPhone, resetting keyboard dictionary, turning off Zoom mode and any accessibility settings that might have any effect on the onscreen keyboard… no change/no effect….. ‘a’ and ‘w’ still don’t work… iOS is version 15.4.1… i’m stumped on this one… so any help appreciated… thanks… JB