Reset to factory state

On an M1 Mac you need to boot to Recovery Mode via holding the power switch from a cold boot. Then you need to go to the Utilities menu and Startup Security and unlock with a local admin account then enable USB Booting. Then you boot back up and you can download Big Sur from the App Store, burn a Big Sur 11.4 installer USB flash drive and boot from that by holding the power button from a cold startup. You'll have the option to choose the USB drive to boot. Then you can nuke and pave macOS Big Sur onto your disk. Delete everything with Disk Utility and install.

If the local admin account doesn't work or doesn't exist, then you may be stuck in a scenario where you will require another Mac and a Thunderbolt USB-C data cable to resolve. This is because Internet Recovery is no longer an option on Apple Silicon Macs. You'll need to recover via DFU mode using Apple Configurator 2 on a working second Mac in a similar fashion to completely restoring an iPhone. However, most of the time this may not be necessary.

https://support.apple.com/en-us/HT201372

https://support.apple.com/en-us/HT204904

https://support.apple.com/guide/mac-help/macos-recovery-a-mac-apple-silicon-mchl82829c17/mac

https://support.apple.com/guide/apple-configurator-2/revive-or-restore-a-mac-with-apple-silicon-apdd5f3c75ad/mac

The devils is in the details of the provided link. Below are those details verbatim.

Revert your Mac to a previous macOS version

If you use Time Machine to back up your Mac, you can easily revert to a previous version of macOS if you experience trouble after installing an update. To select a Time Machine backup from an SMB server, your Mac must have macOS Sierra or later installed.

Important: Reverting erases any changes you made to the files on your Mac since you installed the new version of macOS. To save new or revised files, copy them onto a different disk or back them up before you follow these instructions.

1. Print these instructions.
2. Click the Share button  in the Help window, then choose Print.
3. On your Mac, choose Apple menu  > Restart. After your Mac restarts (some Mac computers play a startup sound), press and hold the Command and R keys until the Apple logo appears, then release the keys.
4. Select Restore from a Time Machine Backup, then click Continue.
5. Select your Time Machine backup disk.
6. Select the Time Machine backup you want to restore. To restore your computer to the state it was in before you installed the new version of macOS, choose the most recent backup that occurred before you installed the new version.
7. Follow the onscreen instructions.

If you backed up files as described in the Important message above, you can restore them now. If you backed them up using Time Machine, click the Time Machine icon  in the menu bar, choose Enter Time Machine, then retrieve your files.

If you reinstall a previous version of macOS on a Mac or partition, new backups will use that version of macOS. If your backups are stored on a Time Capsule or other network storage device, existing backups are retained; they aren’t overwritten by the new backups.

Apple Silicon SoC processors are almost the exact same thing as the mobile A# SoC processors found in the mobile devices, they are merely larger and more powerful. Because they are essentially the same as what powers an iPhone / iPad the need to potentially use DFU becomes much more likely. Long term iOS beta testers have made full backups and it was not uncommon for them to need to DFU reset an iPhone to return it to a production operating system after beta testing. This is mostly due to the stronger security with the Apple Silicon SoC processors, the Secure Enclave, hardware encryption, the lack of a traditional BIOS / UEFI / EFI firmware, Secure Boot, etc.

One will have to Un-Enroll for the Beta Program before attempting to rollback.

Revert your Mac to a previous macOS version

Agree with previous poster and for Future Purposes. Very handy for this occasion too.

 Do I have a Rescue Plan In-Place. This comprises having 3 Backups using 2 methods and 1 Off Site incase of Theft, Loss or Natural Disasters. A Time Machine Backup  is very useful and can be used to Revert to Previous Working macOS. For addition purposes - two Tested Bootable Clones each to separate external drives. This is insurance incase the upgrades goes sideways. At least one Tested Clone and / or Time Machine Backup should be Off - Site

Before testing any developer or public macOS beta you should not use your primary Mac and you should always backup. I would recommend a Time Machine backup in addition to a Carbon Copy Clone or SuperDuper! clone of the disk of the Mac prior to testing.

I typically backup my data. Re-image the test Mac to a clean state with the latest macOS version and patches. Install whatever Applications and custom tweaks I usually do on a new Mac. Then back this up to an external drive, in my case, using CCC. Then and only then will I install a developer or public beta. I also do not use my primary iCloud account, I use a test one. If I am testing a developer or public beta of iOS / iPadOS I use devices that are not my primary devices. Login with the same test iCloud account. You can really mess up your iCloud data if you run a beta on your primary iCloud account as data in the cloud can be modified to only work with the new beta macOS/Apps. Therefore data loss is possible and very difficult to recover if it happens in iCloud.

Definitely do not recommend testing beta operating systems unless you have spare Apple devices on which to test.