BTRFS has a concept called a subvolume. You are allowed to mount it just like any other device. This is an example /etc/fstab I’ve copied from somewhere some time ago.
/efi (or /boot, or /boot/efi, whatever floats your boat) still has to be a separate vfat partition, but all the other mounts are, technically speaking, the same partition mounted many times with a different subvolume set as the target.
Obviously, you don’t need to have all of them separated like this, but it allows you to fine tune the parts of system that do get snapshot.