Request Desktop Versions of Webpages (and Make them Actually Fit)
In iOS 13, there is what looks like a text-size icon in the URL bar; tap this icon to change zoom/font size, show Reader View, hide toolbar (tap the top of the display to show the toolbar again), or Request Desktop View.
Selecting the “Request Desktop View” option will load the desktop site, but it may dynamically fit itself to the smaller screen. To view the whole page, rotate into landscape view, and then use the same menu to zoom out up to 50%. You should see the whole page as it would be rendered on a computer.