I was also trying to figure out how strong Magneto can make himself. I've seen him manhandle Wondy and take punches from a Colossus that meant business. Broke some of ribs as I recall.
But I guess that was a "sucker punch" in that they didn't see it coming.
Magneto can amp his strength to insane levels, but more importantly, his control over metal is absolute. One of my favorite feats is how he was able to use nothing more than tiny metal fibers in his cape to break a bearhug Hercules put him in that Hercules said was never broken before. He had all the leverage, Magneto was previously injured defending against the rest of the Avengers who thought he kidnapped the New Mutants (they were actually his team). Even with all of that, just using tiny metal fibers in his cape, he shrugged Hercules off of him.