That’s your prerogative, but it honestly doesn’t make sense. Typescript adds almost no functionality to JS (and the few pieces it adds are now considered mistakes that shouldn’t be used anymore). It only focuses on adding typing information, and in the future you’ll be able to run TS that doesn’t use those few added features as JS (see the proposal).
You can also add the TS types as comments in your JS code, which IMO shows that it’s not a different language.
JS itself is great, I prefer it to most other languages due to the flexibility that it allows. Adding types through TS to safeguard against footguns doesn’t mean you’re not still using JS. You can also add the types using comments instead if you prefer it, which means you’re actually writing raw JS.