Just a quick update for anyone who comes across this thread..
It was the head gasket (thanks Cujo). They replaced that and I had them do the water pump/timing belt because why not.
Now there is a "clanking" sound on startup, near the dash, that quickly goes away.
Possible loss of performance.. but I don't know if that's in my head or not. Seems to lose power here and there, maybe a slight delay in acceleration.
Not sure if I should try the same garage, request the dealer pay for a specialist or return it. Pretty bummed.