What should I do about not having khushu' (devotional humility) in my prayer due to not understanding the verses, and does that affect the validity of my prayer?

Humility (Khushu') in prayer is important, and the prayer is valid without it, according to the preponderant opinion. If a Muslim cannot know the meaning of every verse, he should strive to sense the general and clear meanings, especially those that indicate the greatness of Allah. There are many things that help achieve humility.