There is a common error about Islam that you cannot read the Koran and understand it. Oddly enough, both Muslims and Kafirs believe this. Many Kafirs believe anything that a Muslim says about Islam. Said another way: when it comes to Islam, Muslims are always right and Kafirs are wrong.
Most of Islamic doctrine is about Mohammed, not the Koran. The Sira is the biography of Mohammed. Can you understand a biography? Of course, you can. The Hadith are collections of what Mohammed said or did. Can you understand an incident that involves a man? Of course, you can.
After you have read the Sira, you can understand most of the Koran. If you have a problem understanding a verse, then go to an exegete such as Ibn Kathir who can explain any verse.
Don’t believe the hype. You can read and understand any part of Islamic doctrine.