If Google owns Search, Gmail, Android, Analytics, Chat, Google Fi, Google Fiber, Chrome, GPay, etc... then they are able leverage one monopoly to establish monopolies elsewhere.
...and that is ultimately what is most destructive to Competition and consumer value. All of the above could be separate companies. Facebook gets a lot of bad press, but Google is the big danger.
You're right that Google leverages its portfolio of services to get a foothold in other ventures, but not one of those listed above is a monopoly. There are solid and well-performing alternatives/competitors to nearly all of Google's services. Their (and Facebook's) online advertising business is another story.
I'm very happy to live in Canada, where Google Pay is completely irrelevant thanks to Interac. I can walk into any business with a payment terminal and know that my debit card will just plain work, no matter my back or credit union. And I can send money instantly online to anyone else who also has an account at a Canadian bank or credit union.
Of course, this means that my bank knows all my transactions, but not using a bank is orders of magnitude harder than not using Google.