I think it's just brand, ubuntu was what I knew from using it as a personal desktop and then it's the default/most obvious option for a lot of providers, I think even 10+ years ago AWS EC2 defaulted to it above Debian, digital ocean too I think?
I don't remember why exactly but it was definitely just 'linux VPS = Ubuntu' for a long time. I think they got reputation as being the 'just works' option because they were happier to include some non-free graphics drivers etc where Debian was the more pure option but most end users didn't care
But since they added snap and I started running into issues with trying to install Docker etc a few years ago I default to Debian now and most of the time I don't even know which it is.
I don't remember why exactly but it was definitely just 'linux VPS = Ubuntu' for a long time. I think they got reputation as being the 'just works' option because they were happier to include some non-free graphics drivers etc where Debian was the more pure option but most end users didn't care
But since they added snap and I started running into issues with trying to install Docker etc a few years ago I default to Debian now and most of the time I don't even know which it is.