IOS 12.1.1 won't sync contacts to google
Did you check in the settings of the Contacts app that the default account is set to your Gmail account? I suspect that the presumably missing contacts ended up in iCloud instead of Gmail. If you set the Default Account to Gmail new contacts created on your iPhone will automatically sync with Goolge Contacts.

Regarding your existing Contacts in iCloud:

The easiest way to move your contacts from iCloud to your Gmail Account is to use the Contacts app on your Mac. Add the same Gmail Account to your Mac and drag’n’drop the contacts from iCloud to your Gmail Account. I don’t think a way exists to do the same directly on an iPhone.