DLSS 3.0 can increase FPS quite a bit, but it does have an issue with blurriness in glass avionics as a side effect of the frame generation. I’m not sure how bad it is but the linked thread might be helpful. That said, the 4080 is still solid and DLSS I’ve heard is quite great outside of this issue!
FidelityFX Super Resolution (FSR) is AMD’s upscaling technology similar to Nvidia’s DLSS, though the quality is generally not as good. But long term, I hope it matches DLSS. We are also still waiting for FSR 3 support for MSFS too.