In this fantastic summary, What Is the Koran? Toby summarizes many orientalist (ie western academic) historic arguments against the mainstream islamic history. He mentions criticisms of the idea that the Quran was preserved intact, criticisms about the origin of Islam by many western scholars, and other great things worth reading. At the very least gives you a high level understanding of some of the arguments against mainstream Islamic history.
It discusses the Yemeni transcripts of the Quran that they found that don’t match the original. Patricia Crone and her “Hagarism”. The criticism of how Makkah doesn’t exist on any trade routes (The Arabian Spice argument), some modern freethinkers such as Abu Zayd.
What Is the Koran?
Researchers with a variety of academic and theological interests are proposing controversial theories about the Koran and Islamic history, and are striving to reinterpret Islam for the modern world. This is, as one scholar puts it, a “sensitive business”
Here is a video summary of some of the orientalist arguments against Islam, but I would recommend you read the above in full.