Rough idle, loss of power and unstable RPM's with CEL

So it turned out not to be so complicated after all but a rather extensive investigative process. I can't for certain say it was this ONE thing that caused the problem, but rather a combination! It was due a service, so I did athe full service with premium parts expecting that maybe the old spark plugs might have been causing the issue. However, the issue was not resolved.

I was getting a misfire on cylinder 4 and 6. Turns out, the mechanics saw oil in the spark plugs and I had a look, and realised the valve cover gasket was leaking. Not substantial enough for the car to be leaking, but there was very visible sludge around the gasket. Had that replaced. I was also getting a MAF sensor error. So I bought some electrical cleaner spray, and cleaned the sensor. Upon re-installation the error disappeared.

Now the code was a misfire on cylinder 1 with no other errors. Simple coil swap to cylinder 2 resulting a cylinder 2 code meant a ignition coil change. And finally, the car is back to normal! It's hard to say which one it was exactly that caused the initial problem or maybe it was everything. If you're having a similar issue, I would start with the cheaper options. Start with plugs unless they've been changed, then coil pack. Look for oily gasket if you suspect that is the problem. And for the MAF sensor, that's a really easy fix with a dozen YouTube videos.