I had heard about most of them but interesting features nevertheless.
Designated Initializers - You probably don't mean "default initialization" because that would imply types without a user-defined constructor, such as int, are left uninitialized which I don't think is what happens.
Spaceship Operator - A user-defined spaceship operator only generates <, >, <= and >=. If you want == and != you need to also provide a user-defined == operator.
consteval and constinit Keywords - consteval is only good for forcing compile-time evaluation if you don't want the function to be callable with runtime values. constinit is mainly a tool to avoid the static initialization order fiasco. It cannot be used on local variables.