Sure, it's not really mysterious. I don't use Microsoft or Apple OSes (I use Linux right now, but I'm transitioning to BSD because I'm not comfortable with the direction Linux is going)
I don't use Google services.
I don't use cloud services or social media. Instead, I run my own servers to provide services that cover the same needs.
I use a custom Android ROM, but ultimately will cease using a smartphone altogether and go back to a feature phone.
As with all things security and privacy related, my approach is an imperfect tradeoff, of course.