I use private browsing 100% of the time. I personally don’t need history, so the only thing history does for me is increase my risk factor. Remember a few years ago there was a bug in Safari that allowed any website to view your full browsing history. No thanks.
If this can’t be toggled, my life is going to become extremely painful. I really, really, really don’t want to have to authenticate every time Safari opens.
It can be toggled. I just tested this on iOS 17 Dev BETA1. And it will require you to unlock it if you go outside of Safari for some time etc. So if you live in private browsing mode, you will still have to unlock it. It doesn't even unlock automatically, and you have to tap unlock for it to do it. That might change of course.
Luckily for you, the entire feature can be disabled in the Safari settings on iOS.