It would be effectively impossible, even if one of those "WRs" were putting up equivalent stats as a TE instead.
Finishing in the top 20 requires a 65/1,000/7 stat line or thereabouts. Stack 3 of those stat lines together and even if those top 3 guys were commanding a 75% target share (well above historical averages), that QB would finish with around 4,000 yards passing and 28 TDs - borderline QB10 numbers as-is. And this assumes those top 3 guys finish right on the thresholds above, when in reality there would be a few hundred extra yards and several extra TDs spread out among the top 3.
Generally speaking, any time three pass-catchers from the same offense are being drafted as elite options, either that offense is poised to set records (unlikely) or at least one of them will be a fantasy disappointment (much more likely).