Check out the posts on here. There is an in-game way to remove it through the console
Viewing post in Syahata's bad day(ver1.0.1) release notice comments
Main page has details, but the specifics are linked here: https://twitter.com/JaShinn4264
https://x.com/JaShinn4264/status/1769003665514528802
Not sure for the game over screen... I never actually found it in-game and had to use the gallery. With all things, make sure it's the latest version etc.