Can one ask for ones rank to be lowered?

Sure, One does not have to accept a promotion, and one can take a demotion. Okay as long as you are not shirking responsibility or doing it so you can goldbrick.

But it is an unwise career move. And may very likely get you a dishonorable discharge.

If you get stressed out by responsibility than you probably shouldn’t be in the military to begin with (indeed, I doubt you would last very long anyway).