Hi,
I suppose if you set a page width to Custom you can achieve greater than 1080, eg; 1440, however, given most monitors that are out there are still 1080p, or the number of laptop screens used, 1080 seems a happy balance to aim for.
Regarding the setup, I pick the lowest res for each of the device types and design from there - means you design for as many users as possible. Of course, if you know your audience is on a set device, you only need to design for that.