Keep in mind with Retroarch on iOS you can use dosbox-pure which can even run windows 98 games. It’s still a work in progress though since retroarch does not yet have good mouse support. Also OpenGL ES acceleration of voodoo graphics is around the corner.

On my M4 iPad Pro I get around 266 mhz p2 performance. With openGL (not yet in the App Store version) you can get ~77fps in quake 1 in glide mode at 640x480.

Pretty much everything of the dos era is playable in dosbox on a m4.