That thought occurred to me as well so I used an adapter cable to plug in a wired USB keyboard. Unfortunately, the issue persists, so it would seem to impact all keyboards, not just Bluetooth ones.
I find it particularly strange that the keyboard worked as expected during the initial days after I installed the game, which was only about a week ago now. I’ve also tried uninstalling the game and reinstalling it, even going so far as to use a file explorer to locate the games files on my phone and manually deleting them.
Edit: I've edited the title of this issue since it is not limited to bluetooth keyboards.
I'm not sure I understand your question correctly, but if you are asking if the keys work in other apps, then yes, they work as expected in other apps. I can launch any other app, such as Chrome in Android and use the external keyboard to type and the "W", "A", "S", and "D" keys all function normally. In fact, I've found that in the game, I can push "T" and then use all the keys, "W", "A", "S", and "D" to type out messages. It seems that they specifically don't work to move the player character anymore, but otherwise are detected and present in the game.