Can you choose not to add your proficiency bonus to an attack roll?

I’m building a very gimmicky multiclass crit-confirmation paladin, and as a part of my build I have a feature that lets me reroll a failed attack roll as a reaction. The idea is that I want to fail at least one attack roll per turn so that I can roll again and potentially get a crit; but the thing is, I’m not sure if I can intentionally not add proficiency bonus to the attack roll of a weapon I’m proficient in. If I’m on the last attack on my turn and haven’t missed yet, can I choose to make a sloppy attack as though I didn’t know how to use a weapon to get that extra chance at crit confirmation?