I just tightened with a 1/4" ratchet, thumb next to socket, bringing it around by closing the fingers, not using the arm .
You can tighten up if it leaks, but once you twist something off, trying to get it as tight as possible, you're in trouble.
Land a bolt about midway on each face, just barely past finger tight, then go to the one next to it, on each face, it's not square, but, top bottom, left right, work around, back and forth , don't hurry. Better to make five passes and pull it down Flat.
Yes, there is a real torque spec, I don't know it, I opened mine , IIRC, three times, and I just did it. I finally tried to go without sealer, and it dripped, and I had to tighten them up past where I was comfortable.

What signs of damage are you seeing?

If you see a leak at a bolt , you may have messed up the rubber seal on a washer, wouldn't tighten it. Wouldn't mess with any of it unless you have a good reason. When it's time to go in, id look closely at the threads on everything. If you get a new bolt, same size, same thread pitch, and it won't screw in as easy as the one that came out, you distorted the threads. That's not uncommon. I've seen a buncha nuts that didn't wanna go back on the bolt it came off of unless it's oriented the way it was.

Don't tighten things, other than head gaskets, with a particular torque goal. FEEL of the bolt. You can feel it stop. Use small tools for small bolts. Well, to be fair, if you're just too strong, naah, you'll pop the head off before you feel it, me, I can feel it.

They put torque specs in the book. Every bolt. Depending on size, thread type and pitch and what it's made of , but that is just what is possible, theoretically, before it explodes. The lower number is another engineering guess.
It's a darn sight easier to snug it up if it leaks than mess it up because you'd feel like a failure if it leaks. Take a chance on a leak,, or a rattle, don't be sloppy, but don't be Andre the Giant.
If you have to get a cheater pipe to get the oil drain plug out,  that's too much..

German torque spec. Good-n-tight!

I think I understand, what you mean. I have a few brand new stainess M6 bolts in the box, when I go back in, I'm going to see how each one threads into every hole. What you are saying is a thread that got distorted will usually only work with the bolt that distorted it, right?