Android 10, Samsung Galaxy Tab A 10.1 SM-T590 (2018), Opera 59.1.2926.54067, ad block off, data savings disabled.
Somewhere between every 10 seconds and every five minutes the Opera window appears to freeze. It's just the display. I can recover by going to the home screen and tapping the Opera icon, and the display is active and anything I typed that didn't show on the "frozen" screen appears in the "recovered" screen.
No idea what triggers it, so I can't make it happen.