> For a number of years now you have to give a phone number to make an account. Doesn't need to be a one-to-one mapping, but it still connects the accounts.
Even if the number is required (a sibling comment challenges that), it only connects your accounts if you only have one phone number, or all the phone numbers you have and use for Google accounts are publicly (or privately but through Google) tied to your identity. Otherwise it does not, to Google, connect the accounts.
I thought they keep track of "associated accounts" via IP address, browser cookies, fingerprinting and so on. There have been plenty of instances where innocent Google Acounts have been terminated due to a different account holder's activity on the same machine.
Even if the number is required (a sibling comment challenges that), it only connects your accounts if you only have one phone number, or all the phone numbers you have and use for Google accounts are publicly (or privately but through Google) tied to your identity. Otherwise it does not, to Google, connect the accounts.