Dell have pre-installed & fully supported Ubuntu on a bunch of their Precision, XPS, and, more recently, Pro laptops for over a decade now.

Those supported models are always a good choice for running other Linux distros, too (I've run a vanilla Debian on 3 different models during that time without having the do anything special).

As I understand it, Omarchy isn't really doing any low-level development work - it's just an opinionated set of defaults & various non-free add-ons on top of Arch. Any laptop supported by Arch will work.