What is the ruling on practicing the "attracting destiny" exercise, which relies on writing a desired matter 21 times daily for 14 days, based on hadiths such as "Be optimistic about goodness and you will find it" and "I am as My servant expects Me to be"?

Good omens (al-fa'l al-hasan) are legislatively مطلوب (desirable) and encouraged, as they stem from having good expectations of Allah. They are the antithesis of the pessimism (tashā'um) that is prohibited. As for the term "attracting destiny" (jadb al-qadar), it has no basis and is an innovation (bid'ah). Destiny is in the hand of Allah alone; He brings it about whenever and however He wills. When a Muslim desires something, they should supplicate to their Lord and have good expectations of Him so that He may grant them their request.