The educated Strix player knows not to attack you when you're in Counter. The key to getting him is to fight fire with fire and be as stealthy and sneaky as possible; and be ready to react when he inevitably pulls out his sidearm.
Do not underestimate the effectiveness of getting really close to them and flying straight up, flickshotting Blastflower down onto their heads. Try to use this against Flankers with exhausted mobility and other Damage champions.
As I said in my Willo vs. Kinessa tip, play carefully and keep moving. As a continuation of that tip, keep Flutter on as low of a cooldown as possible. You can also use your ultimate as a distraction play if necessary.
Play as carefully as possible and keep moving. If you can’t try to flank Kinessa herself, try and capitalize on any moment she isn’t targeting you. Damage boosting Talents like Blastflower or Scorn are best.