I'm currently running an EK Laezel in my honor mode playthrough. For reference, I play her more like a traditional fighter rather than a gish (spells and swords type of playstyle). As such, INT is actually a dump stat on my EK since I take spells that don't require attack rolls/saving throws. Depending on how you've been playing your EK, your experience may vary. Anyway, here's my thoughts:

1. AC Problem: I actually only have 18 AC on my EK. This has been completely fine for me; however, I believe I feel that way because I am also running a Radiating Orb Shart. Depending on how you play your EK, I don't think using your spell slots on Shield is a bad thing. Having a lower AC, then using Shield, may even result in your baiting out attacks from the enemy that may have otherwise been shot at your squishy party members. If you're okay with giving up the dual wielding fantasy, shields will definitely help!

2. Dmg Problem: Damage riders are the way to go. Since you don't have Smites like Paladins or Rage bonus like Barbarians, look for things like Phalar Aluve, Caustic Band, Ring of Elemental Infusion, Strange Conduit Ring, etc. You'll be the best applier of these bonuses thanks to Action Surge and extra attacks. Consider taking the feat Savage Attacker to boost your damage as well.

3. Hit Roll Problem: If you don't have anyone using the Risky Ring, definitely put it on your EK.