Previous versions were made with an older version of the engine that utilized OpenGL. When I updated the game to godot 4 I kinda didn't notice it's now running on vulkan, and later on switching it back to OpenGL did break some things I already implemented in the game, so I decided to just stick with it... unfortunately vulkan is completely unoptimized for older hardware, which is why I'll never use it again, especially since 2d games don't really need fancy rendering engines like that...