If you don't have much experience with Linux, I suggest to just try a few distributions. I've had several of them, I especially didn't like what Ubuntu did to the GUI, so I left them. You could try Kubuntu too, or Elementary OS, or Linux Mint, or Arch Linux, or CentOS. There's also the "classics" like Red Hat, Mandrake, Debian and Fedora.
In general, they're all quite safe, but
some focus more on security than others. But if you have some time to spare, I recommend to just try a few and see which one fits your needs.
I would also like to know if I can re-use my existing "blocks" and "chainstate" folders of my Bitcoin Core windows folder into the the Linux folder to not have to go through the entire thing from scratch.
I'm pretty sure you can just copy it, but I'd prefer to just let it run from scratch.
in order to be able to run a full Bitcoin Core node and forget about constantly being paranoid of doing so in Windows.
For what it's worth: I'm just as paranoid running Linux. I actually consider it a good default, don't ever assume your computer is safe!