You seem to be having trouble with reading comprehension. Maybe you need to read things more thoroughly? I'll try to provide some clarification.

First: you said, and I quote, “Riding a bicycle itself isn’t all that dangerous, even without a helmet.”. That is blatantly, proveably false, especially when you say that it’s not dangerous even without a helmet.

I didn't say it's "not dangerous", I said it "isn't all dangerous", which implies there is some danger.

In 2001, 44% of fatal bicycle accidents–377 out of 853–did not involve being hit by, or hitting, a car[1].

That's not what your source says. "Of the 1,230 bicyclist deaths in 2021, 853 died in motor-vehicle crashes and 377 in other incidents," is what it says, so that 30% that weren't in a direct motor-vehicle crash. Even then, how many were indirectly caused by motor-vehicles? If a bicycle veers out of the way of a car, that's counted as an "other incident". Speed is one of the most dangerous aspects of bicycles and you feel to cycle faster when riding with traffic. Even you previous noted many incidents which are poor infrastructure or maintenance issues.

If she had been in a car, and hit by another car? Yes, I think she would have been fine.

That's the point...cars are dangerous to people not in cars.