God I wish iPad OS was a better developer experience. Github's Codespaces feature is awesome, but as a front-end dev there is no way I could use iPad/iOS to build a website. There is no dev tools. The OS keeps trying to suspend apps/tabs in the background when I switch between them. I use the Vim extension in the VS Code remote editor but certain key combos on iOS straight up didn't register. Maybe I'm asking for too much.
Why don't you use Termius and SSH into the Codespaces instance? That way you could just use vim directly from there.
Also could install a browser based VSCode on that remote server and access that.