What should I do if urine and feces are discharged after relieving myself, and must I ensure that no urine or fecal residue remains by wiping with tissues, knowing that I find it difficult to purify myself completely and spend a long time in the bathroom?

We ask Allah to grant you healing from the waswasah (whispers/obsessive thoughts) you are experiencing. Worship is built upon ease and removing hardship. For istinja' (cleaning oneself after relieving oneself), it is sufficient for you to cleanse the exit point of urine or feces without overdoing it. Then, you must completely ignore the waswasah you experience regarding the discharge of urine or feces, because the best cure for waswasah is to totally disregard it. Ibn Hajar Al-Haytami clarified that completely ignoring them is a sufficient and beneficial remedy for them, and that whoever listens to them will find them increasing until they lead to madness. It is necessary to avoid staying in the bathroom longer than needed due to the health risks involved, as mentioned by Ibn Muflih. It is not obligatory to use tissues for istinja'; it is permissible to suffice with water alone.