WAY more rom than com, and Billy Eichner's obnoxiousness proves insufferable.
I think the film was marketed improperly. From trailer to posters to promotional public appearances, Bros is advertised as a comedy, and Eichner himself says "It's complicated, and I honestly find the whole thing to be very silly when you take a bird's-eye view of it all—it's just a comedy," but it's really not, at all, and that's the problem of identity that undoes his intentions, however noble they might have been.
Had Bros been funny, okay, that's just a swing and a miss, but it's a HEAVY and controversial drama with no funny zingers, so I think people leave equal-parts over and underwhelmed, unentertained, and feeling altogether overdressed for the occasion.