That's pretty normal, especially considering your usage.
Worn piston rings won't cause it, and that's a rare fault on a modern engine. These head gaskets tend not to fail, and don't cause this symptom when they do. Oil coolers do fail, but the oil leaks into the cooling system.
I would:
Do an oil and filter change. I found using 5w30 instead of 10w40 made mine much noisier, and even more prone to leaks.
Remove the filler neck, clean all the gunk off it and the cap, then screw the cap directly to the cam-cover. Use a funnel to add oil.
Check all the usual areas for oil leaks. These engines are normally filthy as they leak from a number of places. Sorting the plenum, breathers and cam covers should be considered necessary for any new Omega acquisition.
Fit six new plugs an inspect the rest of the ignition system - that's probably your misfire. Another Omega 'feature'
Replace the thermostat so it gets up to temperature quickly - it's a modern engine, and it should be hot.
Do a longer run more often.
That list ought to reduce the amount of mayonnaise that the engine produces. Some won't cause any problems, and you just live with it.
I don't see any point in the really short oil changes for petrol engines recommended here, but I'm in a minority.