Unable to install BigSur on a new M1 MBP with Monterey

Unable to install BigSur on a new 14' M1 MBP that came with Monterey. I need to run dual versions for testing reasons.

I've been trying to install BigSur from a USB drive. Installer boots fine, but does not allow me to ANY partitions or volumes as destination for the install. The error when trying to select is **"The update cannot be installed on this computer".**

Same issue as described here for older macs: https://support.apple.com/en-us/HT211242

Sams USB installer is able to install to an Intel 2015 MBP without issue.

I have tried using the following as targets:

1) A new APFS volume

2) A new APFS partition + new volume

3) An APFS volume on an external drive

I also tried doing an "Erase HDD" without luck. It lets me install many copies of Monterey without issue.

**My only option left to try is to restore BigSur using DFU mode,.**

Any ideas?