Still waiting for the dream to be able to write code on an iPad. There are some good native apps out there for checking out Git repos and editing files with syntax highlighting, but I never use them because there’s nothing in the OS that integrates them all. You’re left with switching between them to do something in your workflow, which is disorientating as each one will take up the whole screen and throw away your context. I suppose there might be Shortcuts — I haven’t explored what it’s capable of — but what I really want is a shell.
The closest that worked for me is a Code Server web-app running in a chromeless browser. It works for me mainly because there is a shell. If the editor doesn’t support a feature, I can use a command to do what I need. I don’t have to switch between apps either: I can see what I’m doing and the files I’m doing it to. I can also build and run them code I’m writing. Fancy that!