GCloud DNS Nameserver change stopped propagating
I can see that the record have been propagate correctly.
So to recap my comment for better visibility:
If you want to manage domains purchased from google on another website (e.g. OVH, GoDaddy, Cloudlare, etc.) you must change name servers on domains.google as described here.
This change may take up to 72 hours, although is usually faster.
You can check current state of NS records with sites like whatsmyDNS or by commands:
Windows:
nslookup example.com
Linux:
dig example.com