What is the ruling on following the more cautious (الأحوط) approach when there is hardship and whispers (وسوسة) in some matters, especially if the easier (الأيسر) approach is more probable (الأرجح)?

If you suffer from waswasah (obsessive whispering/doubts), you have a dispensation to follow the easier opinion to remove hardship and difficulty. An ordinary person is not required to follow the stricter opinion; rather, they should emulate someone whose knowledge and piety they trust, because there is no hardship in religion.