How are websites created by the same person "linked" to each other

Lets say theoretically I want to start a second website (website B) targeting the same keywords, leveraging the domain name of this new website in an effort to get a leg up on ranking (exact match domain - i know its not nearly as effective as it used to be, but theoretically I want to try it).

Well, theoretically I don't want Google to know website B is affiliated with website A (my current site). They would say whoa there, same person, same keyword targets, why'd they build a second website, were not going to rank it.

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• If I buy and host website B under the same account, does Google see that? - What data would tie these 2 sites together? Registrar? IP? Is that why I see people selling VPN's on blackhatworld all the time? (this stuffs over my head)
• Is this a valid concern or am I being way too paranoid and wasting time with overthinking?