iPad screen goes black unexpectedly, comes back when tapped but very dim.

iPad Pro 11 inch 3rd Gen running 15.4.1

The screen goes black unexpectedly mid web browsing or using apps - no dimming then black, just straight to off. When I tap it multiple times it comes back on but very dim - almost unreadable. When I call up the brightness (top right of screen) it says it’s where it was previously set (it’s not) and I have to slide it up and down to get it back to previous level.

Battery is at 80%+, screen lock is set at 5 minutes, true tone is off, auto brightness is off, etc.

Anybody have any ideas?