20.04 LTS and B550 motherboard - ethernet problem

First question so apologies for the long one. This is somewhat similar to other posts like this one:

However, I have scoured the internet and not found a usable solution yet. In the images attached you'll see:

1. I tried to install the driver from Realtek, however, the system indicates that make is not installed.
2. Alright, so to do that, I need sudo apt-get build-essential. However, since there's no internet connection, it doesn't know what to do. I tried installing build-essential using the tar file found here , but it indicates that dpkg-dev must be installed to build this package.
3. Tried installing dpkg-dev from the tar file, but apparently there was no acceptable C compiler on the path.

This is installed on a system that has windows on a separate drive - that install of Windows needed the ethernet driver to be manually installed, but I cannot figure out how to install the Realtek driver on the linux system. I've also tried tethering my iphone to Linux, but apparently that has stopped working with iOS 14.

Thanks in advance! Pictures are in the links below:

Ethernet install error :

Build-essential error:

Additional error from dpkg :

1 Answer

Final update for anyone reading this: could not get 20.04 LTS to work, and as a last-ditch effort tried 21.04 and it worked!! Clean install, no fiddling with drivers whatsoever, and the ethernet worked out of the box.