They said  everything is normal and performance is just as expected.  I really surprised. Also ı have a deep knowledge both  VSAN and Nutanix platform i never accept the results by myself. But they said ok and the customers happy with that but i am not.

All the configs made by DellEMC and Support team checked that and everything is fine with the installations. 

And one more thing about NVMEs none of the Nutanix guys suggests using NVME drives they prefer to use ssd drives instead of NVMEs  all the times .