code review as others mentioned but if everyone is on equal footing in the review then you need some kind of enforceable policy where work isn't merged until a policy team signs off on it. Who is on that team becomes a matter of office politics and navigating such. With support of CTO that can be worked out for designated roles among peers.
If the people on that policy team require too much and slow things down in your fast paced environment then that is another seperate issue to navigate to find the right strategies and methodologies.
I eat 2 cups of food for lunch on weekdays because if it was good enough for a roman soldier to march on it's good enough for me to go clickity clack on a keyboard.