I can't see my reports regarding the inventory valuation summary and detail report even they give me access as Inventory Manager in QBO Advanced. What should I do?

You can ask your company admin to give you access to reports to view this, @Mhekang123.

To begin with, the inventory manager role can only view and edit the products and services list and perform other inventory tasks; however, this role is unable to see the inventory valuation summary and detailed report. To solve this, I recommend asking your company admin to check your current role settings and make sure the box for inventory reports access is checked.

I've attached a screenshot for your reference

If you have additional questions, feel free to leave a comment.