When I tried to update it said app not installed because it's conflicting with an existing package.
Do I have to uninstall the game?
yes but dont worry, ren'py (the engine the game was made in) has a cloud based save method, all of the saved progress will stay even after you delete all of the files because it was saved in the same device/cloud, so all of your progress will be there even after you unistall/delete the game and its files