Yes, There IS something to widen: Text. It has been that way until iOS 13 and it is that way on the Mac. It is clearly something WRONG, but I don’t know if it‘s a bug or it has been intentionally removed.
For instance, go to MacRumors.com on a landscape oriented iPad. Go to an article, and double tap to read the text more easily. It doesn’t work. That’s not the supposed behavior. Having to pinch with two fingers is not as convenient as the smart zoom feature was.
What a pity, I’m going to report it ASAP, and most people should report it as well.
This is not a step forwards, it is a step backwards. A good feature that has been removed.