After thinking about your 'manual' remark, my guess is that you meant that you opened the [LinOxide] page linked above, and added the indicated ppa and continued to install and run neofetch (in a terminal). Right?
I managed to find neofetch in another (and a far simpler way) in the repositories. I seem to remember installing this app in a previous version of Ubuntu. It is cute but I prefer inxi (sudo apt install inxi) to examine and display my system specs.
Please see -
for examples.