I ran:
sudo efibootmgr -o 0001,0000
Picking 0001 as the first device to be booted.
The delay is gone.
systemd-analyze
Startup finished in 6.994s (firmware) + 4.346s (loader) + 744ms (kernel) + 3.170s (initrd) + 9.682s (userspace) = 24.937s
graphical.target reached after 9.681s in userspace.
Problem solved!
Thanks, @dalto.