Although scratch is pretty primitive, there's a way to convert scratch files to HTML so you can actually upload them on itch. You use this program called htmlifier and upload a scratch save file. This can be further uploaded to itch using the normal method. The only caveat is that the files contain ALL of Scratch's code base. Link to the Github: https://sheeptester.github.io/htmlifier/
Per usual, I've used the program before BUT download at your own risk
If you want a scratch alternative that requires no code I'd recommend Construct 3. It still doesn't require that much code, only a few lines (that you can look up online) It uses block-based coding, although not as childish as Scratch and designed to be a real engine.