Is it obligatory to make up missed prayers, the number of which is unknown and exceeds 200 prayers, due to obsessive whispering (waswasah)?

You must repent to Allah for abandoning prayer and yielding to the whispers of Satan, for abandoning prayer is one of the gravest sins. You must make up all missed prayers. If you do not know their number, then strive to estimate them and pray what you believe is sufficient to absolve you, making them up in order, at a rate of at least two days' prayers for each day.