Earlier this year, on the outbound portion we had an 8 hour layover in DOH, which we spent in the lounge(s)- ate, showered, got a sleep room for a few hours (... good luck "sleeping" on an S-shaped lounge)

The one thing we wish we looked into was the Doha tours that run out of the airport. Depending on your schedule, it might be interesting (looks inexpensive).
https://www.discoverqatar.qa/transit-tours/

On the return, we arrived DOH at 10:00PM, and our connection was at 7:50AM, so we opted for the Oryx airport hotel. It wasn't inexpensive (~$299USD all-in), but it was super convenient- basically walk from your gate to the hotel. We were happy we did.