Engine Carbon (or sludge?) build-up

[mitsumi]

Hi there,

just want to share what i saw from FB group.
Pic is not mine but regarding the engine the history of it was a 2nd hand engine and problem was it is overheating but when they did a test it all comes down to the thermostat problem of the car.

But my question is how true that by using fully synthetic oil causes this to the engine so early or is this normal? Also he noted that the mechanic told him to buy a carbon gasket instead of the OG i think, but im not sure.

BTW the engine is from a 2014 Mirage as noted by the person who shared it.