formatting NAS HD

I have taken out the HD's from my Synology NAS and I have been trying to format for use as regular HD's, but was not successful up to now.

I got different messages and asked advice from the manufacturer, WD, but didn't get them to work.

I see these messages:

I cannot partition or mount the disk.

Found advice on reddit, quoted here.

so I tried that in the terminal, but got stuck on the third line with this message:

So I put the HD in a new caddy, new cable etc, but still the same messages.

Anybody an idea how to get this fixed??

Thnx in advance!