This.
But having nearly everything in an OS encrypted does hog some resources a little, although not as much as M$. So use a fairly fast machine.
Qubes OS
https://www.qubes-os.org/
Tails
https://tails.boum.org/
BlackArch Linux
https://blackarch.org/
I disagree with the name of this one, but it’s another penetration tester.
IprediaOS
https://www.ipredia.org/
This one is in alpha for now, so it’s vulnerable until more stable. Looks like a promising project to learn about, though.
Subgraph OS
https://subgraph.com/
The following was developed by the Air Force and is NSA approved. ;-)
TENS
https://www.tens.af.mil/download.htm
And if the lack of a certificate there trips your paranoia trigger, you can read a little about it here.
It runs on a stick like Tails, Puppy Linux and others.
that site you linked to is recommending people try russian or chinese operating systems? Nope- No thank you!
Bump for later. Thanks.