Zoans needed a pod, and the Trygon needed to deepstrike. Walking those units is a bad idea, Eldar shooting has too much time to deal with you then.
Also, you didnt mention any Psychic powers. The Tervi could have used Catalyst to offset some of the Dire Avenger/Wraithguard/Wraithlord shooting. And the Flyrant could have done with
IA or Endurance, and also being further away from those Wraithguard.
Podding the Devilgants could also be a fun idea. 10-20 of those in pod has a lot of shots, and could have shot the Dire Avengers right of the objective for you.
I love your Nid scheme, they look fantastic!
A good report, but I think you need to switch up your tactics to put the hurt on the Newdar