Google would have to know who I am before I’d worry about that.

Yes but Cambridge Analytica.

A different kind of weasel.

Your concern about data, if it is sincere, should be aimed at other targets — perhaps they are in your aim too: I don’t know because you haven’t mentioned it if they are. Your isp and phone carrier collect virtually everything you do (location too, as phones constantly triangulate off the 3 nearest cell towers) and it is far more than a fair bet that the sell it to every bidder that comes along. You should also be concerned about the growth in data collection by the government* — started with the terribly named Patriot Act, the amount of which has at the least been left alone and often increased since it started.

I don’t know whether you use the little keyring scan cards grocery and other stores offer — if so, your data is everywhere now: those cards are tied to your identity.

It only take about 12 good pieces of data to identify you — fewer if location data is included. Unless you’ve never used any of the electronic devices that have been prevalent for over a decade, it’s too late to worry about it now. That’s not conspiracy mongering: people are right to be concerned. It is wrong to think or imply, Google is involved in selling what they collect: it’s more valuable to them directly.

* Far short of having any statistical significance, but: I know four people who teach computer security at universities or work in it doing research. All of them have told me that because US border agents have been giving them so much hassle when they leave or come into the country (computers/phones are taken for examination while they wait and returned after different amounts of time) that they’ve started wiping their computers and phones clean before they travel. Nothing but bare stuff on them — they ca access what they need after they are at their destination. That’s the stuff to be worried about.

Take a look at what google has on you. Not sure if Iphone does the same.
https://myactivity.google.com/

Letting Google keep your browsing habits on file is probably not a good idea.

Not as as bad as unjustified paranoia.

Fixed the headline for you. Letting Google keep your browsing habits on file is probably not a good idea.

My biggest concern is that there are URLs I must visit now and then that Google habitually sees as insecure

A big part of that is flagging as insecure sites that still use http rather than https. Eventually the plan is to make it more difficult to access http using sites.