What is the ruling on a prayer that I completed, having intended to repeat it due to lack of devotion? And what is the ruling on prayers after which I found secretions but was unsure of when they exited? And is going to perform ablution considered an intention, and is it obligatory to bring the intention to mind? And what should I do if I doubt whether I performed a make-up prayer and cannot remember, given that I suffer from forgetfulness and obsessive thoughts?

Your prayer, which you intended to repeat due to lack of devotion, is valid and you are not required to repeat it.

And your prayers, after which you found discharge and you do not know whether it came out before or after the prayer, are valid, due to the possibility of it having come out after the prayer.

The place of intention (niyyah) is the heart, and your intention to perform ablution and prayer is in itself a niyyah. So, do not utter it verbally, as it is not legislated, and do not succumb to excessive whispers (waswasah) regarding the intention.

As for the prayers whose performance you doubt after their time has expired, the preponderant opinion is that there is no blame upon you for disregarding this doubt and not paying attention to it, especially if you are forgetful.