Why do I have gaming time in a game I haven't played

Sometimes, when a game does not meet the requirements of the system, it may freeze idle or minimised until you shut off your computer. It may have frozen and minimised instead of closing, which would cause an extra couple of hours on the steam timer. You may wanna contact steam support with your issue, and if they can't help you, you could always keep it for a later day when your computer is stronger.

Another thing is that in PUBG, even if your computer is terrible, you can try a few matches and get items, and win a small portion of your revenue back on the Community Market.