Unbeaten 49ers keep surprising each week

San Francisco 49ers defensive end Nick Bosa, right, celebrates with middle linebacker Kwon Alexander (56) after recovering a fumble by Cleveland Browns quarterback Baker Mayfield during the first half of an NFL football game in Santa Clara, Calif., Monday, Oct. 7, 2019. (AP Photo/Tony Avelar)SANTA CLARA — Lots of people thought the 49ers would be good this season.

Not many thought they’d be 5-0.

Sure, the schedule broke in their favor. They haven’t faced a good quarterback yet, because Ben Roethlisberger had season-ending elbow surgery and missed the Steelers’ Week 3 game against the 49ers. The highest-rated quarterback the 49ers have faced is Roethlisberger’s backup, Mason Rudolph. And the…