My guess is he stays with the 1500 until after the 2021 World Championships, which is Especially Big since it is in Eugene , Oregon. Then he moves to the 5000 (Note The Diamond League is saying that the 3000 will be the longest race so maybe he moves from the 1500 to the 3000?)through 2024 and probably tries to Compete Through 2028 with the Olympics being in Los Angeles, after that maybe he tries the Marathon, People will be interested even if he is past his prime as a former Olympic Champion running a Marathon, regardless of how he does if he runs 2:10 or 2:30 it does not matter he has marketability based on his Olympic Gold, it will be intriguing to Track Fans.
As for it being his ceiling, I doubt it, the 3 Runners ran that in a LOW KEY MEET, USUALLY people run their best times in BIG MEETS Oslo, Monaco, Zurich, Paris, Rome, Brussells etc, they may have had PERFECT pacing (In my opinion Ahmed may be the best of the 4 in a race right now) but they don't have the adrenaline from performing in a packed Stadium, with all the Worlds Best there and a History of great performances, I hope someone tries to force a fast pace in Doha and lets see how fast they go.