Blocking countries with high risk fraud

Do you guys block any countries to access your site?
I looked into some high risk fraud of credit card and chargeback, USA turns out to be with the highest rate according to Grok research, followed by Brazil, Mexico, Pakistan, Bangladesh, Venezuela.

Do you guys block any countries for these reasons?
What are other preventive measures do you guys take to prevent credit card and chargeback?

Usa at the top don't make sense, it could be because of most sales and hence most charge back.
You can temporarily block vpn and datacenter proxies access to your sites and see if it helps.
If the sales - charge backs is small number for last 5 countries you can ipaddress block those 5 countries.