Heres a couple of things that have worked for me:
I think your temps are too high, thus its cooking instead of drying.
Try starting with a cold smoker, and set to 160. As you know this will heat up for the first 20 min. but the smoke will be profuse. Leave it in with door closed for 2 hours. This will be where you will get most or all of your smoke flavor.
At the 2 hour mark, open the door to the smoker and LEAVE IT OPEN for the rest of the smoke. This is where it will dry. (The door is cracked open a couple of inches, not wide open) Set the temp for 200. Since the door is open, it will never actually attain 200, but in my experience the actual internal temp of the smoker will be around 160. If it is warmer than 160 inside(check with one of your remote thermometers), than decrease your smoker controller setting accordingly until the internal smoker temp is 160. Since the smoker is trying to attain the preset 200 degrees, it will continue to heat the wood and smoke will continue.
Total time on my jerky runs 6-8 hours with this method.
There is a cookshack video on the topic as well, on their website or youtube channel.
Hope I am explaining myself well, please feel free to ask questions if not. One last thing, I am typically using Hi Mtn cures, not a wet brine, so this may affect your total time to smoke.
Good luck. Don't give up. Take notes.