I did a couple more tries ,i double checked bios that nvme ssd is first in boot order ,and again happened the same.
Beowulf + LXqt will install successfully in nvme but after reboot will stop to a grub prompt with no error .
I managed to boot the kernel with:

grub> set root=(hd3,gpt2)
grub> set prefix=(hd3,gpt2)/boot/grub
grub> insmod normal
grub> normal

but the kernel booting suddenly stops in a blank screen with a curson on top left where i can see letters i press.

The same procedure as above will work if i try Beowulf + XFCE .

Also there is no problem so ever if try a sata ssd.

I will be patient. Also i want to add that the error message error no such device xxxxxxxxx..... (that is the UUID of the partition that was holding my previous debian system ) was appearing also just after grub menu when  i was booting with debian. But i didnt dwell over it because my system was booting ok. Also that debian systen was my fiirst try to install in a nvme storage.

So i suspect that that nvme storage of mine maybe is  related here.

Ok, i managed to boot folllowing different instructions in grub2.

grub> set root=(hd3,gpt2)
grub> insmod linux
grub> insmod normal
grub> normal

After booting into (just after grub menu goes away i see:
error no such device 1fe9bf88-.....  (that id is from my new devuan partition)
but after some seconds it goes away.

in my text only Beowulf system i give:
# update-grub

and
# apt-get install firmware-amd-graphics

Now i booted in XFCE , i dont have connectivity!! (i had in text mode previously!)

Installation medium: Beowulf netinstall
Host: a headless vps somewhere north europe !

I installed runit .
But only gettys run under runsv . Does that mean that apache , rsyslogd , sshd , dhclient as services do not have a runit ''interface''?
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I found a page with runit runscripts scripts. Should i use those?

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Ok, they helped me at #devuan irc.
If i got it, runit defaults in sysvinit when it wont find runit scripts.