While I couldn't exactly reproduce the issue reported at https://forums.freebsd.org/threads/trying-to-install-on-dell-latitude-7390-uefi-nvme.67468/#post-401759 I was able to select da2 when I tried installing from a USB stick, which was the USB stick itself. You can't do any damage, ie it just fails to write to the disk, for a first time user it must be awfully confusing.