Disable shaders

Hi! I’m making a game that doesn’t require any shader, any model, material or something like this.
I only use the UI.
I found that about half of the game weight is for in-game graphics, that I don’t want.
How can i disable it?

Use forward rendering. Also, unless your making a simple visual novel or point and click game, you need shaders and models and stuff like that. 2d games do need collision n stuff like that and can benefit from things like faking 2d with a 3d camera.

Thanks for your answer, but no, I simply use the UI, the player will never see a character, an object, a sprite, nothing like this. Only widgets with buttons, text and a little bit of images.