What should I do about not mastering the recitation of Al-Fatiha in prayer, despite my repeated attempts to practice it, and my fear that my prayer will not be accepted?

Learning Al-Fatiha is obligatory for every Muslim, and prayer is not valid without it. Whoever makes a mistake in Al-Fatiha that alters its meaning, their prayer is invalidated, unless they are unable to pronounce it correctly. It is advisable to present your recitation to someone knowledgeable in Tajweed to help you correct any mistakes. If you are unable to do so, then recite what you can, and your prayer will be valid. Do not open the door of obsessive doubt upon yourself.