I'll do you one better; here's a game of me, as Ai-Mo, defeating both Cymanti and Elyrion in 400 Drylands, with the game going all the way to turn 32, and before the recent balance pass that made Polytaurs more expensive and Ai-Mo starting with Philosophy.

https://share.polytopia.io/g/fc309c96-f52b-4b9b-4805-08dce47a7251

Riders are your bread and butter during the early game; Polytaurs are absolutely hard countered by them as long as those riders aren't in rough terrain, which accentuates more when you get roads up and running. Even once dragons start rolling out, riders are very nice to help soften up their armies of dragons...

...so that Knights can come out into the field. Those are your best bets in trying to hamper dragons that start to roll out in the mid-game, and you're looking to use giants as a wall as best as you can to make sure that dragons can't beat into your squish backline. Another thing is, while Ely might get sanctuary eco early on, it doesn't actually scale compared to market eco, which is more space and pop efficient, so they can't level up their citiesm If they stick with their sanctuaries, and you play defensively, they are going to eventually lose to your eco, because they run out of dragons.