I flew the Ethiopian route from IAD-ADD-WDH in February, but only had about 1.5 hours on the ground each way. I don't believe there is a ton to do in that airport, but I'm not sure about hotels/lounges given my quick turns.
I'm also a United guy, and it was good to get the miles for that trip, but we wouldn't plan to fly Ethiopian again if we have other options in the future. Our airplanes were old with fairly dingy interiors, packed completely full, and many of the passengers made huge messes and were generally disrespectful to those around them.
Ethiopian also played games, switching airplanes around constantly between booking and the flights - with the worst change being that they swapped our airplane from ADD-IAD just before we landed at ADD. They changed all of the seating - placing a 3-4 year old boy between my wife and me, and his mother a row or two behind us - and completely filled a 777 that had been scheduled with new 787 with some available seats, for the 14ish hour (with 1.5 hours on the ground to fuel in Dublin, during which we weren't allowed to get out of our seats) flight to IAD...all within an hour or so of departure. All that said, they got my rifle and me through ADD in time to depart both directions.
We were initially booked with Qatar until they dropped the routes during Covid. We'll definitely look at Qatar again in the future since they've picked the routes back up.