I second this recommendation. I have been dual booting Ubuntu for many years on my gaming PC's and recently bought a pre made Ubuntu machine from Dell. The least fun I ever have when installing a new machine is trying to get my fucking three monitors working the way they should.

The Dell laptop plug and played into my (not thunderbolt, wd15 or something dock) and all three monitors were literally plug and play. It felt like Windows again and blew me away.

I also recommend Thinkpads T series or X1. Mine works great with Fedora (and formerly Ubuntu). Awesome keyboards

Love System76, my favorite laptop is light little Lemur.

The XPS 13 with the i7 and Max ram is a great machine. I liked it so much I made it the standard equipment for my ops team.