sudo apt-get update not working!
You can change the repository that figures there
http://download.opensuse.org/repositories/home:/strycore/xUbuntu_16.04
,that dont have a release file for this one:
http://download.opensuse.org/repositories/home:/strycore/xUbuntu_18.04/
If that doesn't work, you should delete that repository, i tried to enter there and i found that it donest exist anymore(the version is no longer supported), sor you could try the 18.04 or delete the first
You can search a way to add repositories searching on google how do that for you SO(i think that is Xubuntu 16.04)