I installed Ignited via SideStore. No Jailbreaking necessary. Not computer tether. SideStore can renew the side loaded emulator every 7 days when on WiFi. The iPhone is perfect for DS emulation with a stylus.
(Ignited is a fork of Delta with more options, and SideStore is a fork of AltStore, with no computer tether needed)
Can you do that on Android?
Yes. It’s even easier on Android. Look for RetroArch. It emulates a bunch of consoles.
I don’t know how it works in RetroArch, with Delta/Ignited you can change the skin which also manages the size and position of the screens. I even designed custom skins to play full screen with no controls with Zelda since you don’t need the abxy and arrow buttons to play.
Can confirm. I played so many games on DRaStic over the last few years. Zero issues.
Of course, some games are not well suited to a full touch screen, especially if they require quick coordination of both stylus and D-Pad. They are relatively few though - most games work great.