Artboard width and height.
The Artboard width and height has Physical width and height of mobile phones. Shouldn't be the resolution of the phone. While exporting the screens in png and viewing it in phones. The resolution is small. Because the physical size of the phone and resolution of the phone differs. Just a small thought
Thanks for inquiring! Unfortunately, this is not how mobile phone OSes (or developing for mobile OSes) work. Often, these devices have what’s called a virtual pixel or a virtual point. A great explanation of this is in the Apple HIG guideline.
XD actually supports this quite well through its export workflow. You can read more about this here: https://medium.com/thinking-design/protip-exporting-assets-in-adobe-xd-c586996de703
Hope that helps!