This is a pretty good video explanation on why Linux is the most secure family of operating systems available, from Mental Outlaw on Youtube: https://www.youtube.com/watch?v=ZYWPyTRXssg
Some main reasons why Linux is naturally more secure than Windows or MacOS:
There’s some debate for whether you are better off with an antivirus program on Linux or not. We mostly agree with the idea that an antivirus by its very nature has to reach into every area of your computer to monitor things, which is a compromise of the natural security and partitioning of the Linux system.
Chris Titus video on hardening a Linux system: https://www.youtube.com/watch?v=V-GYYrsNNSM
NetworkChuck video on hardening a Linux server: https://www.youtube.com/watch?v=ZhMw53Ud2tY