What is the ruling on one who has missed a few prayers due to obsessive-compulsive disorder (OCD) regarding ablution (wudu') and prayer, and how can these delayed prayers be made up in a way that does not cause psychological distress?

The cure for obsessive thoughts (waswas) is to disregard them and pay them no heed. If you have prayed, do not repeat the prayer, no matter how much Satan whispers to you. If you perceive something to have exited you, your prayer is fundamentally valid unless its invalidity is certain. If you perform ablution (wudu), do not repeat it, and do not exceed three washes for each limb. If you feel distress during your prayer, seek refuge in Allah from Satan, continue with your prayer, and do not interrupt it. There is no harm for you in adopting the opinion of those who do not consider it obligatory to make up prayers intentionally missed, as long as you are afflicted with obsessive thoughts.