I'm also new. How many replies are required to "join the club", so to speak?
My seats removed easily. I put the right sized metric socket with a short extension onto a 1/2 inch breaker bar. Held everything square & plumb and applied steadily increasing pressure.
If bolt heads are rounding off something's wrong. They shouldn't be near that tight, but maybe they are. Put some Viener Schlider on 'em and let it soak over night.
'O course, there's always the heat wrench...