Google runs their own, Facebook runs their own, Amazon used AWS, Microsoft uses Azure. Netflix uses AWS.

Most likely all are running some version of Bind, or something custom.

And if you’re wondering about the hidden authoritative servers (that the company uses to generate and administer the zones then synced to a global DNS provider such as the ones you listed) two rather popular products for companies that aren’t also cloud providers are Infoblox and BlueCat.