Is it permissible to adopt a fatwa that mandates not waiting for urine to exit after relieving oneself, not inspecting or being cautious, and not paying attention to any feeling of urine exiting after ablution or during prayer, in order to alleviate the suffering of urinary incontinence and obsessive thoughts?

What the shaykhs have advised you is correct. What you are suffering from is merely a feeling caused by obsessive thoughts (waswasah) regarding purity, stemming from the devil's imagination. Fatigue, boredom, and waswasah are not justifications for abandoning prayer or being negligent with it. Maintain your prayers and make up for what you have missed, for your neglect of prayer is the devil's goal. Trust in Allah and rely upon Him, and increase your acts of worship, such as reciting the Qur'an, performing supererogatory prayers, and engaging in dhikr (remembrance of Allah). The cure for waswasah is not to indulge in it, but rather to seek refuge in Allah and to turn away from it, along with continuously reciting the two Mu'awwidhatayn (Surahs Al-Falaq and An-Nas).