RIS/CAS... depends on usage, the version that is in ReShade is too sharp even at lowest setting of 0.0 that's supposed to be a "disabled" setting. I prefer lumasharpen with my own settings and more adjustment.
For some source that's heavily AA nuked, sure CAS may be fine with it's stronger sharpening algo.
Scaling pixel art... just use an emulator that outputs native resolution and has what ever scaler you want or can add your own. Adding nearest neighbor/integer scaling takes 10 min.
RIS/CAS is on any GPU via ReShade. Or you can copy paste the code from AMD's source to what ever you want.