1.1.1.1 is an Ad blocking DNS not a VPN. A DNS server turns URLs into IP addresses. Google DNS and VPN and you will understand they are very different.
Hmm, then I wonder if the VPN may be blocked or restricted by your provider. Or maybe quality control issue.
As much as I love this phone and have had no issues, I do admit Google may have some serious quality control issues with their phones. 
Hopefully you find a fix!
After you open the Google One app, push up from the very bottom of the screen and hold. Wait about one to two seconds until you see other cards appear to the left of the Google One card, then let go. Finally, swipe up on the Google One card and it will have been “force-closed”.
I had surfshark as a sub prior to replacing it with Google one’s VPN, didn’t have the same issue, so I’m hesitant to say it’s a phone issue and more likely a Google one VPN issue, but could be wrong
Yeah, then maybe it’s a dud or quality control issue, I’m sorry. :c