Prius Left on for 4-5 Days (!) - Problems?

Bottom line up front - an airport parking valet left my 2010 Prius on for several days and now my dash display is a little wonky. How concerned should I be?

Took a trip this week where I had to leave it with an off site airport valet parking lot. Handed off the car with almost a half tank of gas, returned and the mileage was the same, but the low gas light was flashing and I had about 20 miles til empty. Also checked the trip info and even with ~3,000 miles on Trip A, showed an average of 15 mph, which isn't remotely correct. All this leads me to believe it sat for an extended period of time (I was gone for 5 days), cycling on and off. It did still have a very small amount of gas left, and was not running or turned on when I got in the car, but fired up like normal.

Drove it to a gas station and filled up, but then noticed that my dash display lighting was weird. The mph speed number brightness was off and always changing levels of brightness as the speed changed, and on the display that showed energy generating/power use, I could actually also see the faint text of "Key not Detected" in the background, like it had been burned into the screen (is that even a thing anymore?).

So, did this screw things up? With a half tank of gas and alternating on and off, guessing it could have run for days? My Yellow Top AGM battery is 7+ years old - when the original needed to be replaced, the dash started doing weird things. Did this just push it over the edge? Any concern for hybrid battery?

Thanks for any advice. Needless to say, I'm about to have a nasty convo with the parking company - just want a sense of how much/if any damage this could have done.

Thanks
Brandon