I am not trying to say PHP > TS, just wanted to let you know in case you still work with PHP codebase that you can get good enough type checks with PHPDoc, here is a good example for the case you mentioned , in Intellij the built in linter will mark as warnings when you use types wrong
https://i.imgur.com/NqlAsTd.png (zoom a bit out and sorry for the bad crop)
About the array issue don't we have same situation with JS and TS where you don't have dictionaries or hashmaps in the standard library and you have to use array or object ?
I like JSX too, maybe some PHP template would be made to copy JSX , but not all ages need to be that interactive and not all PHP code is rendering HTML, my current project uses angular1 for the frontend (it was something already created so there was no debate what tool to be used where I could have voiced an opinion).
As a personal opinion I prefer react to angular because I don't like the angular magic compile stuff, I like that react components are JS functions and I can breakpoint into a render functions. I also done some side toy projects with TS, I like it and I hope it gets more popular so new projects would use it but I am worried that we could get a wave of front end languages and we will not have a standard great language but many non standard languages.