Head Gasket issue , Coolant burning/mixing in the piston, white mayonnaise substance

I had all the symptoms of a head gasket issue in my Vauxhall Corsa 1.4 ltr (2012) A14XER Engine.

1. Mayonnaise like white/light brown sludge everywhere. Rocker cover, Oil Dipstick, Oil Filler Cap. Attached an image of the rocker cover gasket after removal.

2. Coolant loss. I would have to basically top up coolant every trip because every time I check the next morning , the coolant level would be so low as almost empty from the Coolant expansion tank and coolant isn’t leaking outside as Ive never encountered any coolant drips externally.

3. Steam coming out of the tailpipe even after a long trip. Would be really visible on colder nights especially.

That being said, the car ran smoothly, no issues whatsoever except for an engine oil light indicating low oil pressure.

So I removed the engine head today and inspected the head gasket and to me it looked fine. There was no visible damage to the gasket so Im wondering what could have cause so much coolant leak/burn/oil mix in the engine to give me all of those symptoms.
Attaching images of the head gasket from 3 different perspectives.

Gasket right side up view:

Gasket upside down view:

Gasket horizontal view:

It could be a warped head which I need to get it tested, but if the head is not warped or the engine block is not warped, what else could cause the above symptoms.