The only things JSON has over xml is that it’s easier to write a parser for it and the format is less verbose and less complicated. There are extensions to JSON that can add features that xml has and the JSON spec doesn’t have. Overall the xml spec is bigger and has more features but that also makes it overkill for many of the cases that it would be used in.
If your primary exposure to programming is only typescript or JavaScript maybe you shouldn’t be jumping straight into something like rust. JS is a high level language and rust is aimed at the lower levels where things can’t be as automatic. There are many languages out there like C#, Kotlin and Swift that will help you get used to the idea of strong types and immutability.