Will one who wished for insanity to be relieved of religious obligations be held accountable, and do the two testimonies of faith become binding upon him thereafter?

What was mentioned does not necessitate renewing the Two Testimonies, for expressing the severity of whispers (waswas) and wishing for insanity due to their burden is not disbelief (kufr). One should not wish for insanity, for intellect is a blessing. Whispers are treated by ignoring them and not giving in to them.