Somewhat early but very usable. Check out the environment on Replit. We are exactly targeting your use-case. Feel free to email us with feedback amjad@repl.it
If I may be so bold as to make your case for you, a huge pain point in the amazing software that is makecode arcade is that it pigeon holes you into TypeScript strict mode, which, while an amazing and flexible technology for seasoned engineers, it is a a very limiting and confusing convention for young learners.