Technical requirements
We'll start with the same Ubuntu Server and Alma virtual machines that we have been using throughout. We'll use these to look at a normal BIOS-based GRUB2 configuration.
To see how the GRUB2 bootloader works on an EFI-based machine, you'll need to create another pair of Alma and Ubuntu Server virtual machines with the EFI feature enabled. To do that, create the initial VirtualBox setup for the Alma and Ubuntu machines as you always do. Then, before you start up the machines to install the operating system, open the Settings dialog box. Under the System menu, click the Enable EFI checkbox, as shown here:
Then, install the operating system as you normally would.
To look at a systemd-boot environment, you'll need to create a virtual machine with Pop!_OS Linux. Enable the EFI feature as you did for the Alma and Ubuntu machines, and install the operating system...