I'm the oddball in that boxers actually cause more dysphoria for me.
I'm a guy with insanely huge thighs and hips and a gigantic butt. Needless to say, passing is basically impossible with this build that T and weight loss have yet to help with. With boxers and even boxer briefs, if I buy the "correct" size, my thighs won't fit into them. And if they magically happen to work somehow, it's basically cutting off my circulation when I sit down. My thighs are THAT big. In order for my thighs to fit into the boxers/boxer briefs, I have to buy two sizes up, which leads to an insanely baggy crotch that hangs REALLY far down.
The way in which dysphoria comes from wearing these types of underwear is that fact that my thighs and hips and butt are so freaking huge that I actually can't wear them properly.
So instead, I wear briefs. They help hold my packer better anyway.