TS is a must for long-term code which should be maintainable in several years by teams. Any lead engineer with responsibility for some crucial app and dev team not using TS is doing something wrong. But using TS comes at a cost. Even when you are savvy in TS you won't bang out code like with pure JS.
But especially in prototyping phases you need this fast-paced coding. And using TS or any type system slows you down, even when you are familiar with typed languages. Often your final code faced many iterations and I sometimes like to introduce TS later, usually at a point where I just need types but not always and as default from the first key press. In early stages I still try to test ideas, algorithms and their general feasibility and a fast 'mind-to-code' interface is crucial and types would stay in the way then.
Further, finding the right type can take some time, just google what type a React's children prop should be and find long discussions. Welcome to the TS-what-type-is-actually-xy-rabbit-hole. And declaring everything as any shouldn't be the answer.
A big drawback are also TS error messages which are super hard to grasp. You get there and you even find tutorials just for understanding TS error messages but it's unecessarily infuriating.
Moreover, VSCode, its TS language server are amazing pieces of tech but here you face also strange behaviours. Types get full Intellisense support while interfaces don't which doesn't make sense. So you need still to go the definition yourself and it's not that IDE-like feeling you hoped for or people told you.
In my setups, I use TS instead of Babel but use both JS and TS files in one code base depending on the requirements and situation.
So, my message is, yes TS is great, has probably the best type system but the tonality by its community/users needs to be much more balanced and less fanboy-ish. I just can't take devs serious who praise TS to death. This is just not true. More, maintainable code is also not just created by a type system but also sane architectures (eg React) and many other factors. Types won't make bad code maintainable. So, types have their place but not everything in TS-land is shiny.