With the latest Windows 11 Beta Channel build 22000.194, Microsoft added Trusted Platform Module (TPM) 2.0 requirement for Virtual Machines (VMs) too, which means a Windows 11 build running via virtualization won't receive further updates if the player doesn't satisfy the newly added requirement. Essentially, VMs will also have to fulfill the same criteria now as the host systems.
Likely in preparation for that, Oracle seems to be working on a new driver implementation for VirtualBox with the help of which the new driver should be able to perform a passthrough and use the host PC's TPM module for overcoming this new Windows 11 criteria. The VirtualBox Changeset number 90946, added on the 27th of last month, lists this new change.
The changeset 90946 states:
Security: Start implementing a driver for passing through a host TPM, bugref:10075
It is possible that Oracle was internally aware of the upcoming Windows 11 TPM necessity for VMs, which was officially unveiled by Microsoft about a couple of weeks later with the Beta Channel build version 22000.194.
Other VM options, like VMWare, also offer the option for virtual TPM (vTPM) enablement on its Workstation Pro platform.
Microsoft says that a secure PC is at the forefront of its Windows 11 vision which is why it has been stressing so much on its necessity, and even VMs aren't getting a pass.