Errors:
Failed to load VMMR0.r0 (VERR_SUP_VP_UNEXPECTED_VALID_PATH_COUNT)
(Note that the newer version of VBox also needs MS Visual C++ 2015-2019 which was not a prerequisite before.)
Reverted back to older version 6.1.26 (Windows 10) and all working fine again.
The issue is with the VirtualBox host software. A VM such as Whonix that was functional in an earlier VirtualBox version should also be functional in a newer VirtualBox version. Therefore the issue is with VirtualBox, not Whonix.
I don’t think any fixes can be applied to the Whonix source code to resolve this issue. No help for that can be provided here.
Check VirtualBox website. Search term:
site:virtualbox.org VERR_SUP_VP_UNEXPECTED_VALID_PATH_COUNT
Or search for VERR_SUP_VP_UNEXPECTED_VALID_PATH_COUNT generally.
If nothing is applicable, a VirtualBox support request and/or bug report directed at virtualbox.org will be required. See VirtualBox Bug Reports for hints. (Whonix is based on Kicksecure.)
Also: Testing with a Debian VM
Agreed to that and I was wondering what if we continue to use older VBox? Will that create any security issue with newer release of Whonix? These changes by VBox in 7.0.20 don’t seem like a requirement for Whonix, right?
I tested whonix with vbox 7.0.20 on windows, no issues on my side.
Whatever you are facing is either your PC hardware, Host OS or Virtualbox itself issue.
Preferably no, always try to use the latest stable version of the software because it comes with tons of fixes whether security and compatibility or features.
Side note: Windows 10 is deprecated, use windows 11.
I am trying to narrow down the issue but only this workaround works and there is no clear answer on this even on VBox forums. MS heightened hardware requirements for Windows 11 multiple times going from unsupported to becoming unbootable and of course the totally wonky updates ready to cripple performance even further. 
Create a new forum thread if your issue is different or post in the existing one if it’s the same issue. See VirtualBox Bug Reports for hints.
The only chance of getting this resolved is if you are working with upstream, VirtualBox. Otherwise this most likely won’t be resolved.
related:
I did stalking of your profile 
and I don’t know how you are so patience answering even these basic and pretty sure repetitive questions for years now. Your passion is next level and I am sure that hat guy in the Whonix padlock is you! 