Kotlin has a few things that TS doesn't have but overall, I'd rate it very similarly. I probably enjoy writing TS a bit more than Kotlin.

EDIT: TS also has Opaque Types, sort of. They call them "brand types" or other names, it looks like this:

    declare const opaque: unique symbol
    declare type Opaque<T, K extends string> = T & { readonly [opaque]: K }

    type Email = Opaque<string, 'Email'>

    function mkEmail(email: string): Email { return email as Email }
    function takesEmail(email: Email) { console.log(email) }

    const email = mkEmail('foo@bar.com');
    takesEmail(email);
    takesEmail('wrong'); // error