Sure, like all systems, there are overhead costs involved. But with something like a typed system, the overhead costs are minimal compared to the benefits you reap from them.

One of the projects I worked on during my transition to typescript was to convert an existing project into it. Sure there was a lot of head banging against walls at some point to get the types to work out, but during that process I finally really understood how everything fit together and gained a sense of assurance that I could use a return of a function with complete confidence. Developing on that project afterwards was also a breeze, moving faster and more confidently knowing that the object types were set, and that guardrails were in place to prevent myself from shooting my own foot.

It's a new system to work within the guidelines of, but guardrails are there for a reason, to prevent you from falling off a cliff.