I have another system with FreeBSD on the 3rd disk.
menuentry "FreeBSD" {
insmod part_gpt
insmod ufs2
search --no-floppy --set root --file /boot/loader
echo "$root"
kfreebsd /boot/loader
}
works there.
But not on this system with nvme ssd's.
Thanks for the help. I have no more time for this.