My Prius 2012 model 2 is using oil

I have a Prius 2012 Model 2(?) I believe. It has almost 300,000 miles on it. 298k to be accurate. I am the only owner I bought it new. I leave in Dallas, TX.

I have done all the maintenance and charged the oil every 10k like the manual says with 0W-20.

At my last oil change at 290k my service guy at a Toyota dealership said it was low on oil. I have know this guy since 2008 so I trust him.

I have put 2 1/2 quarts into it since that oil change. I am at 299k so almost ready for the next oil change.

It does not smoke out the exhaust, leak oil, the engine does not make strange sounds.

What could be causing it to buy oil?

Should I think about buying a new car soon?

thanks.
David.