Forgive an unsubstantiated theory here, but I expect it would be easier as a director known for dramatics to make a comedy than the other way around. There is humor to be found nearly everywhere, after all (even serious-minded Stanley Kubrick made "Dr. Strangelove," a soaking-wet satire that takes the flesh off your bones even as it makes you guffaw), and the serious-minded director need only turn their calibrations a few percentage points to turn something dramatic into something genuinely laughable (unless you happen to be Ruben Ostlund, in which case you like having the dials set precisely between the two).