United Kingdom

This report gives the opinions of expert behaviourists and consultants on the reasons why some dogs may be aggressive towards people. Of the 215 experts who responded, some 74% argued that breed was either not at all important or only slightly important, whilst an overwhelming 86% believed it was due to the way that the dog was brought up by its owner.

https://committees.parliament.uk/writtenevidence/90096/html/

The law on dangerous dogs refers to specific breeds of dog as ‘dangerous’. However, we believe that breed-specific legislation ignores the most important factors that contribute to biting incidents – primarily anti-social behaviour by irresponsible dog owners who train their dogs to be aggressive or do not train their dogs adequately.

https://www.thekennelclub.org.uk/about-us/campaigns/dangerous-dogs-deed-not-breed/

https://www.theguardian.com/uk-news/2023/sep/11/banning-some-dog-breeds-in-the-uk-wont-stop-attacks-on-humans - study in comments

There is a ton of research on the issue.