You can do that using the following command:
sudo nvram "recovery-boot-mode=unused"
This sets a firmware variable in nvram indicating that you want to start in Recovery mode on the next boot, and then reboots the machine.
When done in Recovery mode, run the following from the Terminal in Recovery mode:
nvram -d recovery-boot-mode
This deletes the firmware variable so that the next boot is a normal boot.
If Recovery boot fails and you cannot progress, you could also remove the firmware variable by holding down the keys Command, Option, P, and R during boot. This resets the nvram and thus the firmware variable.
>sudo nvram internet-recovery-mode=RecoveryModeNetwork<br>
>sudo nvram internet-recovery-mode=RecoveryModeDisk<br> within Big Sur 11.6 on VirtualBox 6.1.28 and none of them worked. Seems that at reboot nvram vars are just ignored and Guest OS skip booting in Recovery Mode.