I'm still using the original iPhone SE (you know, the small phone with bezels). The design of Safari for iOS used to be perfect. The + sign to open a new tab was right in the middle. Switching to incognito was 1 tap away. The open tabs were stacked open behind another.
Apple redesigned Safari in iOS 15 to accommodate it for the bigger all-screen iPhones. The address bar was moved to the bottom for better reachability. The + sign was moved away not to be so close to that horizontal line that replaced the home button. Incognito was hidden away. The stack of open tabs become a grid.
Even though the redesign made sense for the bigger bezel-less phones it was a regression for phones like the iPhone SE. I would have loved if they introduced the changes only to newer models but I can also understand that maintaining 2 different UIs would've been more work.