Apparently, Feral has developped specific libraries to port DX12 games. I haven't seen reports on performance of the macOS version, but the Linux version of the game is basically as fast as the DX12 version. I suspect the Metal version will not run as well because Metal is quite different from DX12, but Feral again did an awesome job with this port.
He said DX12 Like apis, Not straight DX12.... It sounds like they were using calls from further up inside the engine, and calling metal from there. Metal3 has many features that are similar to what youíll find in dx12, which is why the game requires 10.15.
The Mac version runs on intel gpus... Canít say the same for the Linux version.