For example, typescript is a fantastic language for marshalling data and UI state since it uses substructural typing instead of nominal typing. Libraries like kysely / other ORM libraries are great examples too and easy to use, whereas in fully typed languages like Rust you would end up having to use a macro library like sqlx or having to define structs for each of your types (which would increase compile time & size)
This depends entirely on context. In the Benjamin C. Pierce school of thought (a common choice in programming langauges research; see his book Types and Programming Languages, 2002), "typed" means what we typically call statically typed, i.e., the language employs a static analysis to prevent the compilation/execution of (some subset of) faulty programs. Meanwhile, languages that are commonly called "dynamically typed" are, in this school of thought, not typed (or "untyped"). (TAPL provides a more rigorous definition, but it's in the other room and I am lazy.)
They naturally use types for compilation, but the type system is trusted to forbid some invalid states. Underneath it’s all bits and bytes.
Even in safe languages you need deserializers/parsers/validators.
Typescript actually ends up having more checks because it runs Javascript underneath (although some might argue those barely count).
For runtime types I've leaned on Zod or Effect schema,which can also generate static types for you.