Galaxy Tab A9+ 11" Screen Issues

Looks like this has come up a few times before, but has anyone found a fix for the screen not waking up? Mine is very temperamental, sometimes responding to double-taps, mostly not, sometimes responding to pressing the power button once, sometimes not, so I know it's not a screen issue. I've rebooted, factory reset, removed case, switched on screen sensitivity, all with no joy. I can remove the screen protector but I don't want to as they're pricey, I've used this exact brand on a dozen or so phones and tablets with zero issue, and this also wasn't a problem when I bought the tablet in December, but was after a subsequent update (maybe Feb?).

It's less than a year old, so before I go complain at Samsung, just wondering if there's another fix.