Bonus points if it has the ability for users to define static analysis a la borrow checking.
That exists today, it's called Rust. You don't have to use async.
So yes, if your whole reasoning is "other people might use async and then I won't be able to use their code", then you'll be waiting indefinitely for the magical programming language that's both fully featured for your work and does not have any portion of the ecosystem implemented in async code.