Look op, you kind of want to drive around without wanting to put in the work to either lern how a car works or what the road rules are.

Security is not something you install and the you got it.

I highly suggest to learn what the common risks are and how they work, then how to counter them.

This whole security and privacy thing requires both effort and knowledge, that is why corpos fuck over people so much, because they ain't willing to put in the work to care.

P.s sorry I reread my answer and I come off a bit harsh, what I mean is that by prompting a community like this with your kind of questions like if we were an AI will not work towards getting you good answers. You need to learn first and one of the first lessons is that there is no security and a casual "I will be opening sketchy files". A better question is: how can I open sketchy files and still be safe?