We have better wrapper software available nowadays, but I was really surprised at how Starcraft II launched. The Windows version of it only included a D3D9 renderer.
Notably, every major game before this point that had a native macOS version, also supported an OpenGL renderer on the Windows version. Specifically in my case, my experience with Wine back then wasn't ideal, and I believed that if SC2 had just had the OpenGL renderer, I could have gotten along fine with it.
I don't expect D2:R to be using Vulkan on any OS, or else that would have made x86 macOS support relatively easy. With my limited macOS usage in Mojave and Catalina, two MMORPGs (Guild Wars 2 and FFXIV) used Wine wrappers. Can't quite remember what GW2 did, but if I recall FFXIV, it used D3D11 -> Vulkan -> MoltenVK. Surprisingly worked well, but I don't know if that was something any random user could have done with any other game easily (not sure if there were pre-compiled solutions around).
Bootcamp should be fine, at least on x86 Macs. I've heard some initial work being done with M1 Macs, but I doubt anything ideal will exist by the time D2:R releases.