Is my prayer valid when I suffer from obsessive-compulsive disorder regarding ablution and prayer, and I recite Al-Fatiha without tajweed, despite adhering to the rules of recitation, and tajweed is difficult for me?

You must avoid and get rid of obsessive whispering (waswasah). Some aspects of Tajwid (rules of Quranic recitation) are obligatory, while others are recommended. If you pronounce the letters from their correct articulation points, then your prayer is valid, even if you do not observe some of the Tajwid rules. You should not be over-meticulous in your recitation and in observing the articulation points. Rather, recite naturally and do not succumb to the whispers of Satan.