Compositor based upscaler similar to FSR or NIS (or literally have those implemented into Blender)

I'm aware quite a few people have suggested adding AI upscaling to Blender, but to my knowledge it'd be hard to do. Each AI is trained on a game or certain types of photos/videos, not only it would still take time to upscale each frame depending on a computer so it might not be worth it since the quality of the image wouldn't be as amazing as native when putting untrained images into it (or take just as long to render). My solution: Scrap the AI part of it.

FSR and NIS have both proven to be able to work on multiple and older GPUs with minimum quality loss. They're not perfect, but we're not looking for perfect, especially a lot of creators who are using Blender for a hobby and not actual work. They work fast and given some extra processing time after rendering a frame I’d imagine they could generate a good quality image. Perhaps you just need an pixel edge sharpener.

AI’s denoising has proven itself to be a crucial step in rendering speeds, but I don’t believe AI will be used for a long time to render out untrained scenes, so we should implement a Filter/Compositor based upscaler for now and wait for proper AI upscaling for the future.