Start using the correct arm to throw. I'd brave the right leg muscles harder at the plant and try to get the elbow forward farther and rotate the body later. AKA lengthening the pause to get to the right pec position prior to pushing with the left leg, twisting the hips, turning the shoulders and chopping the elbow straight. You reach back higher, swoop lower and keep a fairly flat possibly slightly rising line thereafter. The rising tendency toward the end has to stop. In putting push the hips forward fast straight at the pole or if you are giving the disc some fade compensation to the right of the pole the alignment of the body and pushing the hips needs to move straight at the aiming point.
Flat shots need running on the center line of the tee and planting each step on the center line. Anhyzer needs running from rear right to front left with the plant step hitting the ground to the left of the line you're running on. Hyzer is the mirror of that.