Can't get Safari out of private browsing on iPhone

In the tab overview the bar at the bottom is a row of tab groups you swipe sideways, not a toggle. Tap the two squares icon, then swipe that bottom bar from Private across to the one that just shows a number of tabs, or to Start Page. Tapping the word Private while you're already on it does nothing, which is what trips everyone up. You can also tap the group name in the middle of that bar and pick from a list. The Screen Time restriction works the other way round, it removes private browsing rather than forcing it, so that isn't what's going on here.