Without knowing the itinerary, dates etc, it is difficult to say whether this journey would have qualified for free stpc as a cash ticket. Generally speaking, it would be unusual if there wasn't an earlier connection operating sooner than 24+ hours.

Avios tickets often have less availability than cash, so you may be presented with fewer/longer options than a cash buyer. But being an avios ricket removes the option for free stpc anyway. You could look at the paid stpc package to see if you qualify. You may prefer to take that option. But you get no choice of hotel, unlike the Discover Qatar ones, many of which are cheaper anyway.