I thought that it was a surname as soon as I saw it, like
Delano,
Delaney,
Dylan,
Declan..
This source is probably incorrect, but it makes the most sense to me:
https://www.mom365.com/baby-names/baby-names-search/d/dulan?m=1
There's a possibility that its Chinese as well, a combination of
Du and
Lan, but I'm not so sure. In fact, I'm not really sure if its a common practice in Asian countries to name your child after a place, or even for the child's name to coincidentally sound like a place name. I know not!
https://www.behindthename.com/polls/356294https://www.behindthename.com/polls/356351https://www.behindthename.com/polls/member/181370