Allow me to say that it seems, lots of things/issue are not clear at your end. (may be mis-interpretations or limited information etc)
like
- Man written
- Written After prophet’s death
- Contradictions

However i will be more than pleased to advise (Insha'Allah) and clarify as much in my capacity.

So kindly list/pinpoint the issues you think are contradictions within Quran and as per you might be/ possibly the mistakes of men writing it...

Await your input in totality to assist you as i can.

Thnx