Ask HN: Most secure personal computer setup?

I am becoming more and more paranoid with who has access to my data. So I am trying to find the best solution for keeping data off other peoples hands.

With that in mind I would like have a solution which require fairly simple instructions to use.

I could set up a different machine which has the most secure OS (which is ?), a Tor browser, use VPN as default but what else ?

I am looking for keeping my shit secure and as much as possible keeping people out of my personal computer(s).

How do you guys go about this, specifically with security in mind ?

Thank you!