If you are using servers from Dell, HP, or Lenovo, download their "Customized ISOs." These include specific drivers tailored for their hardware. Steps to Install ESXi 6.5

Navigate to the "VMware Cloud Foundation" or "vSphere" section.

Look for the "VMware vSphere Hypervisor (ESXi) ISO" file.

If you'd like to dive deeper into getting your environment running, tell me:

you're using (e.g., Dell PowerEdge, HP ProLiant).