Hello!
Most latest powerful computers are compatible with Linux.
Just one thing: keep away from NVidia Optimus technology.
There is also not the best support for ATI switchable graphics cards.
Although Linux community created a solution which is the Bumblebee Project, in this regard NVidia and ATI failed. Things work but it would rather be better to pay attention to graphics cards that are listed as Linux supported. This is the main area to look at when considering Linux powered laptops.
Everything else is quite well covered and you can fallow the better specs the laptop has the better performance you will get.
Dell seems to have interest in providing Linux powered computers again. Might be worth a look at.
Also there are System76 computers
https://www.system76.com/laptops/however keep in mind that DaVinci Resolve Linux version appears to be built using RPM packaging method. I would suspect it should work on RED Hat, Fedora and Centos Linux. But if System76 runs Ubuntu as main supported OS, there shouldn;t be problems with drivers in Red Hat kind Linux OS. The most important thing is to know what Linux OS does DaVinci Resolve support.
As you come from MAC world, you already can afford expensive hardware, knowing MAC and PC price differences usually MACs are more expensive so I think you will not have trouble getting intel core i-7, atleast 8gb ram, Nvidia Card with Cuda (Cuda would really speed up things if you run software that use Cuda)
I run Davinci Resolve 9 Lite on Windows on Dell XPS L502x with intel core i-7, 8 gigs ram, 2GB Nvidia GeForce 540m, and it is blazing fast. Pro version should be even faster.
And in Linux, most software run faster usually, so with similar spec pc you should be good to run Davinci Resolve 9.
Since Lite version is not available for Linux I can;t tell for sure, but judging from how it works on Windows, any portable workstation level laptop should do really well.
Kind regards