Culture at Series A startup

I've just started working at a series A startup (with ops/sales heavy business). While it's still a start-up, coming to the office in person 6 days/week (alternate sat off) and mandatory 9 hour attendance on Zoho is something that puts me off.

People just want to stamp time, rather than actually be efficient and get most things done. And because is all this, the speed is also slow.

Curious to know if it's just me or do all series A startup after hitting 50 employees become mini corporate