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)
As for stylus, I’m using this. It’s a capacitive stylus (works on iPhone, unlike apple’s pencil) but it’s battery powered to keep a thin point and high precision vs the rubbery knob stylus.