Or maybe - and this is what I'm honestly inferring from your comment, it's not snark, it's just a hunch based on 16+ years of web development experience - just maybe there were issues with your teams code quality that means TS has been a huge win for you. Looking at that stack, it seems like someone in your organisation likes sticking plasters over problems.
I'm not a Javascript apologist by any means. I think Typescript makes an already quirky and clunky language worse.
Yep, sticking plasters over problems describes it perfectly ;) Many refactoring attempts, but never completed, because JS makes it really hard. And yes, code quality is bad. Most of it was written by people who never wrote JS/HTML before, then it grew historically and here we are with this mess.
But besides TS being very helpful in a messy code base, personally I would also always start a new project with TS. For me the benefits greatly outweigh the minor annoyances (I really see them as minor)
I'm not a Javascript apologist by any means. I think Typescript makes an already quirky and clunky language worse.