I had an 8 hour layover in Doha earlier this week. We booked Oryx in advance and paid for it, and I'm glad we did. The airport was fairly crowded, we were tired and it was nice to have a safe space to take off the mask and order room service. There was a fairly long line to check in, but most of the people had not booked in advance and were turned away quickly. So if you're thinking about it, I'd book early. Have a nice trip!