how to get repeating letters on 2019 16" MacBook Pro keyboard
Since 2011 default behavior in Mac OS has been for letter keys to not repeat when held down. Instead the Character Picker or Accent Menu appears where appropriate. Nothing to do with the link you mention.  To get repeating keys, try opening Terminal and typing

defaults write -g ApplePressAndHoldEnabled -bool false


and then restart.

In Pages if you press and hold e, you should get what is shown below if your OS is working properly.