>> What’s notable is the performance of the Rosetta2 run of the benchmark when in x86 mode, which is not only able to keep up with past Mac iterations but still also beat them.
There currently isn't any kind of useful virtualization available for Apple Silicon, and my hunch is that there won't be until ARM becomes more relevant in the Windows/Linux space.
The way Apple Silicon runs x86 apps through translation makes virtualising x86 systems either impossible or at least extremely difficult.
The answer to all three of your questions is "If you are worried about this, absolutely do not buy an M1 Mac." Rosetta 2 cannot magically turn VirtualBox from a virtualization management system into a high-performance x64 emulator. The long-term solution is probably going to be running ARM Windows or Linux in a VM and leaning on Rosetta-style compatibility/translation in the client OS to run x64 programs.
Edit: Since this is attracting downvotes, maybe it needs some clarification. The things OP asked about fundamentally cannot work. Rosetta 2 is designed exclusively for user-mode programs and cannot cooperate with virtualization software to run arbitrary OSes in VMs. VirtualBox has no plans to port to ARM and will not work in Rosetta. None of this is negativity or cynicism towards M1 Macs - it's just the reality of how switching architectures affects virtualization. If your use case for Mac hardware is to run arbitrary x64 code at high speed in VMs, you should not buy an M1 Mac because that capability does not currently exist.
