You can download the Dell Customized VMware ESXi 6.7 U3 ISO directly from their support site.
Look under the tab if the standard version is listed as "not entitled". Vmware Esxi 6.7 U3 Download Free Iso
Similar customized versions are typically available on their respective support portals. Key Technical Details for 6.7 U3 Release Date: August 20, 2019. You can download the Dell Customized VMware ESXi 6