optiscaler/OptiScaler ? reverse-engineered prompt

Build me a tool for PC games that can sit between the game and the upscaling tech it already uses, so I can swap the in game upscaler for another one without changing the game itself.

I want it to work in games that already support DLSS, FSR, or XeSS, and I want a simple in game overlay where I can choose the input and output upscaler, turn frame generation on or off when possible, and tweak things like sharpening and quality settings. It should also save settings in a config file, and have a clean setup for Windows with a basic Linux option too.

If some parts need current docs or game compatibility info, look that up online and make sensible defaults. The end result should feel like a real modding utility that launches easily, shows an overlay in game, and lets people swap upscalers and frame gen with minimal fuss.