Unless something has changed radically since MacOS Server failed, Apple would either need to do massive software engineering of a sort that they are unfamiliar with or they would need to use a different OS entirely to have a credible cloud offering. Mac OS is unlikely to be able to compete with Linux or FreeBSD in the near future even if the CPU is magically better.
They could have a very bare bone macOS based server operating system specialised for running virtual machines. Dont they have their own xhyve virtualisation layer?
Federighi mentioned during some interviews after the Big Sur presentation, that macOS is a great hypervisor for vitualisation, when asked about Linux on AS Macs. Running Linux in the cloud would equally easy.
