In a way the ARM64 package “slipped out”, and it’s not expected to work reliably. The implementation isn’t complete yet (which is what you saw), and in top of that the performance is known to be extremely low. It isn’t anywhere near production ready, we know. This will not change for VirtualBox 7, and the “Technology Preview” marker will stay for the foreseeable future, indicating that it won’t be supported at all.
Also worth mentioning that they are first working x86 emulation on ARM, ARM-ARM comes later.
Treat the M1 build as a very very early technical preview please, the Beta label is completely misleading and will be changed (this comes from the automated build system and aligns with the rest of the builds). There will be no official support for M1 with 7.0, not even for ARM virtualization, let alone x86 emulation on ARM.
And just for clarity (based on additional questions being raised in the forums): VirtualBox is not and never has been an ARM hypervisor. The M1/M2 developer preview relies on an Intel code simulator module to run x86 (32bit) single core guests. Incredibly slowly. It’s currently more of a toy than a serious solution to any problem.
“never” is an awfully long time. it’s an open secret (visible in the dev source code repository on virtualbox.org) that we’re working on making the x86 emulation on ARM better (faster, less buggy, …). This should eventually be good enough to run the usual 32-bit and 64-bit Windows versions and many Linux distributions. We’re also working on ARM-on-ARM which will allow you to run Linux distros supporting aarch64 (and once Microsoft makes it possible to get a legal version also Windows/ARM).