Hi there,
Win10 is soon not supported. Tbh Linux have been on my radar since I started to break from the US big tech.
But how is security handled in Linux? Linux is pretty open-source, or am I not understanding it correctly. So how can I as a new user make sure to have the most secure machine as possible?
To have the most secure machine possible, you might need a hardened kernel but you absolutely need to have SELinux (or equivalent) rules set up.
The easiest way to have a go at this would be to install OpenSuSE (any version will do, they all ship with SELinux ootb) and follow guides on how to setup SELinux permissions.
Or Fedora