Termux is much, much better than iSH. iSH is not bad, it's just that it doesn't run any code natively, everything runs through a software emulation layer (I believe x86 to the Apple Axxx processors). So it's slow. Whereas Termux is native and very snappy. I tried running emacs on my iPad Pro (2017) and gave up because it was too slow. On Termux emacs is great, even on a midrange phone from several years ago (Moto G5 Plus).