TypeScript seems better (or at least on par) typing wise to Python.

I don't think anyone is picking Python for it's type system. It's still a second class citizen at best.

Common misconception. You have startups choosing a language while trying to absorb unsustainable operations costs to justify using the wrong language instead of picking the right language from the start.

Until 7 years down the line you have to round up a team of your most experienced engineers and add some to figure out how to scale the frecking' thing.

This is an outcome most startups pray they are lucky enough to see.