That type of driver is not supported with 7.0.
"Did you find this helpful? Let us know by completing this survey (takes 1 minute!)"
Hello James and welcome to the forums!
First of all, Scott's answer is correct: As of today there is no Realtek NIC driver that works with ESXi 7.0.
The latest version of ESXi that works with a Realtek NIC is 6.7, and even with that you need to use the community supported net55-r8168 driver (see https://vibsdepot.v-front.de/wiki/index.php/Net55-r8168 ). So you should be able to build a working ESXi 6.7 image with the switches -v67 -vft -load net55-r8168.
However, the error that you are seeing with the script is caused by incompatible SSL encryption settings on your system. There is a suggested fix in this Github issue, but it doesn't seem to work for everyone: