Ok, I finally had time to attempt a fix for 19.10 with 5.3 kernel. Secure Boot needs to be disabled so check
Code:
mokutil --sb-state
If it is not installed or says Secure Boot disabled then
Code:
sudo apt install git dkms
git clone https://github.com/jeremyb31/ath-5.3.git
sudo dkms add ath-5.3
sudo dkms install ath-5.3/1
Reboot

If it fails and you have no wifi, reverse with
Code:
sudo dkms remove ath-5.3/1 --all