Always tweak setup of what you have to optimize it fist before changing anything!
Try listening with less direct exposure to the tweeter output.
Try listening off axis from the tweeters and see if the fatigue is reduced or eliminated.
If it is, try setting up speakers so tweeters fire to either side of your listening position and not as directly at you, so you are listening at a similar off-axis angle.
Then play with the distance between speakers and distances to rear and side walls to avoid early reflections until you hear a nice balance of tonality without fatigue, soundstage and imaging, and bass levels.
Try listening with less direct exposure to the tweeter output.
Try listening off axis from the tweeters and see if the fatigue is reduced or eliminated.
If it is, try setting up speakers so tweeters fire to either side of your listening position and not as directly at you, so you are listening at a similar off-axis angle.
Then play with the distance between speakers and distances to rear and side walls to avoid early reflections until you hear a nice balance of tonality without fatigue, soundstage and imaging, and bass levels.