I believe the iSH app[1] can run Emacs without jailbreaking the iPad. I use it a lot, but not for Emacs.
So a warning: Long-term exposure to this code may cause loss of sanity, nightmares about GAS macros and linker errors, or any number of other debilitating side effects. This code is known to the State of California to cause cancer, birth defects, and reproductive harm.
I tried emacs in it once and it was too slow to be usable - would be keen to hear if you get a performant setup.
Or just run alpine with openssh and ssh in locally through an iOS client. I'd be curious how running UTM/qemu continuously would affect battery life. Is it 10% or 50% less? 10% would be an acceptable trade off for me.