Second, if the only interviews you get are "whiteboard coding", and the only rejection is "not a cultural fit" you may not be interviewing in the right place. Not all places want you to be a 10x engineer who's gonna work 80 hours a week.
I'm surprised you encountered this behavior in larger companies. You said you got introductions from your friends, I assumed you interviewed there. I would try to get more constructive feedback through your friends to really know what's going on.
Second, if the only interviews you get are "whiteboard coding", and the only rejection is "not a cultural fit" you may not be interviewing in the right place. Not all places want you to be a 10x engineer who's gonna work 80 hours a week.
I'm surprised you encountered this behavior in larger companies. You said you got introductions from your friends, I assumed you interviewed there. I would try to get more constructive feedback through your friends to really know what's going on.