it:9 http://ppa.launchpad.net/obsproject/obs-studio/ubuntu focal InRelease
Reading package lists... Done
E: The repository 'http://download.opensuse.org/repositories/home:/strycore/Debian_9.0 ./ Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details
Hi @kj_plays, welcome. I do not know why you have opensuse repo in Ubuntu (assuming you are running Ubuntu MATE), perhaps it is providing some driver or package that is not available in UM. In any case, if you just click on the link for opensuse strycore repo, it shows 404. That is the reason you are not able to update. If you go one step back, you will see only Debian 10 listed not Debian 9.
So, possibly changing Debian_9.0 to Debian_10 as http://download.opensuse.org/repositories/home:/strycore/Debian_10/ in your sources.list will help you update. If you don't want to deal with command line, in Menu, select 'Software & Updates', select tab 'Other Software', highlight the line for the strycore repo and click on 'Edit'. Change 9 to 10 and click 'OK'. You should then be able to update.
