Oil and coolant on spark plugs?

Let me start off by saying that I recently purchased this car. Prior to that it’s been sitting for the past 5-6 years. The only thing I’ve done so far is put a thermostat in, change the oil and put an alternator in. I also did a radiator flush, and the coolant had a little brown in it.

I did a compression test on my engine after white smoke was intermittently coming out of exhaust. I’ve also been losing coolant, so I wanted to do this test to see if there is a head gasket leak. My car doesn’t overheat or lose power. But it does have a rough idle only when the engine is cold. It will rev up and down for approximately a few minutes, or until you start driving. After that it doesn’t do it again until engine goes back cold... I just recently changed the oil. The oil wasn’t milky like if coolant was mixing into it, but it was very black.

I did the compression test and found out quickly that oil is on almost all the spark plugs. Then there’s one cylinder which I believe coolant is getting into. Because the ignition coil smells like coolant, and it’s the only coil that’s brownish.

I did some research on head gasket leaks and was thinking about trying blue devil gasket repair. I see a lot of mixed reviews but it’s a 30-year-old car, so I figured I’m not losing much if it clogs up something. But if that works that would only solve my coolant leaking issue I believe? I’d still need to figure out why oil is getting into the spark plugs. So, I was hoping someone could point me in the right direction.

Any help is appreciated, I don’t have much experience with working on cars. I’ll include pictures of my compression test; spark plugs and ignition coils.