the environment you would work on is Linux based, obviously (which it often is when servers are involved, even with Microsoft due to Azure cloud and containers)
you master the command line, i.e you know a bit of e.g bash, can write your own scripts that do basic functions
you understand how the OS works, i.e permissions, services, package managers, etc
but not really if you are mostly clicking through buttons of the window manager and/or would work in a Microsoft environment with its own set of tools, conventions, etc.
Which brings up obvious suggestions :
do improve your mastery of the command line
apply to jobs that put Linux forward (but that might bias to a sysadmin position, which might not be what you prefer)