Restoring full previous Safari tabs on iPad

If you closed a Safari Window - and all associated tabs - you can reopen a Recently Closed Window for a limited period of time…

Starting from a Home Screen, assuming that Safari is visible in the Dock, touch-and-hold (i.e., long touch) the Safari icon; an Action Menu will appear. 

From the menu, select Show All Windows; you will now see a screen that closely resembles the Task Switcher - but you will only see preview windows for your open Safari Windows. At top-right (iPadOS15) or top-left (iPadOS16/17/18) you will see the Reopen Closed Window(s) button.

You should note that the Reopen Closed Window(s) button allows you to reopen a window for a limited period of time. If left too long, you may have lost the opportunity to recover the closed window - and with it the tabs and related tab history.

The above recovery description applies explicitly to iPadOS/iOS. I have tested this more than once (usually having accidentally closed an entire Safari window) with excess of 500+ open tabs. All tabs (with associated history) were successfully recovered.

The "200" limit that you describe will be encountered if you attempt to individually recover closed tabs from the Recently Closed Tabs menu (accessed using a long-touch of the "+" icon at top right of an open Safari window).

Re-opening closed tabs from within an open Safari window is an entirely different function to re-opening a recent closed Safari window along with its previously opened tabs.

Try the procedure that I have outlined; it works. To test, open a fresh Safari window (remember, iPadOS multitasking allows you to have multiple instances of the same App - such as Safari - open at any one time. Open multiple tabs within your "test" Safari window - then deliberately close the window using the App Switcher page, or using the "..." multitasking button at top centre of the Safari window. When the Safari window has been closed, follow my original process to re-open the closed Safari window.

There is a time limit within which the option to reopen the closed window is available. I have never tried to ascertain precisely how long the closed window remain available, but the option is many minutes. The option will not survive a restart of the device.