I've pondered quite a great deal about this very same question. I'm the owner of a 2015 MacBook Air, and I'll probably won't buy another MacBook when mine dies.

What I'll definitely do is get a Thinkpad Carbon X1 and put elementary OS on it. The Thinkpad line has been around for ages and are praised upon. It's fairly linux-friendly, and elementary OS is a great distro, stable enough to work on, and its polish and attention to detail resonates with a MacOS user.

I've been using elementary OS on a VM in my gaming PC and it's been working flawlessly. Really like this distro.