Alternatively just tap on any one of the other open instances. Tapping this will recover the last closed Safari window. You will be presented with a screen containing all the open Safari windows (instances) - and in the top right corner should be a “Reopen Closed Window” button. With both the Safari window and dock visible, simply tap the Safari icon. Don’t use the flick gesture as this will return you to the last used home screen similarly, don’t swipe upward to the centre of the screen and pause - as this will invoke the task switcher. If this happens to you, from your remaining Safari instance, swipe-up from the bottom edge of the screen just enough to reveal the dock. With the new OS, many Users who have not learned about the new features are opening a second (or more) instance of Safari - and inadvertently closing (or simply hiding) an existing instance together with its open tabs. In iPadOS, you can now have multiple App windows (instances) of the same App - including Safari. If you accidentally close a Safari window, you can restore it together with all its open tabs.

How to reopen closed window