The solution listed in one of these worked to get the wired connection finally working. I have copied the solution and pasted it below.
" I downloaded the driver from the realtek website to get the 2.5G Ethernet LINUX driver r8125 for kernel up to 5.6
From a Terminal window run:
sudo apt install r8168-dkms (this package was needed in order to run the r8125-90004.01 diver script with no errors)
cd /home/username/Downloads
cd r8125-90004.01
sudo chmod +x autorun.sh
sudo ./autorun.sh
sudo reboot