Hardware manufacturers often maintain their own repositories for customized ESXi images that include specific drivers.
Similar customized versions are typically available on their respective support portals. Key Technical Details for 6.7 U3 Release Date: August 20, 2019. Vmware Esxi 6.7 U3 Download Free Iso
Look under the tab if the standard version is listed as "not entitled". Vmware Esxi 6.7 U3 Download Free Iso