On your point about junior devs working on backend. I think part of that is that asynchronous programming is just hard. You have to have a brain for it. Some stuff you can get away with (front-end, for example, if you miss an event after an animation it’s not the end of the world), but for serious back-end systems you have to know how to handle async no matter what language you’re in.
Have you looked into Remote Tunnels?
You can control your Desktop VSCode remotely from an iPad browser. You’ll still likely need a keyboard and a trackpad or mouse will help a lot, but that’s basically the same situation as CodeSpaces.