Hi and welcome. You came to the right place for form review.
Overstepping the tee is bad for health, gives you a penalty if the disc hasn't ripped and you're called on it and makes critique not accurate on how you would drive normally. Not to mention huge variances in aiming.
Your arm swings in hyzer fashion and the follow through step lands in hyzer spot (left of the running direction) while the running direction is anny. Limits of flexibility and therefore inconsistencies can occur there. I would see what keeping waist posture straighter through all axes does for distance, accuracy and consistency. It will take a lot of drives to determine accurately what the differences are. Hundreds preferably to a minimum of 50 in field practice in calm warm weather with hard dry ground. Theoretically a straighter posture should be better. And you need to be able to maintain posture in the follow through too for best results. It may require stomach and back muscle workouts and obliques will surely help in D.
How often do you miss angles nose and hyzer? If you ever get those issues i'd test making a pre throw stand still pre whip or not at all then check the disc orientation in the hand and only then start to move for the real throw. I've heard that the pre swing is only effective for 6 seconds so the throw must be completed before that. It was just one study and this is second hand info so i have no clue as to the real situation. Once you train you can tense up the outer layers of the arm muscles momentarily standing still then do a mental exercise of when you accelerate the arm and then do the throw pretty violently.
With little practice i got it to feel almost to as good as the pre swinging during the throw on good days. It probably also depends on how warmed up and rested you are. I have too little no pre swing experience lately to say how it goes. Because i can't hold on to the disc long enough any differences with the methods dissipate there. I can only relate how the arm working feeling goes. It doesn't make a huge difference in distance for me. When i adopted the pre swing during the motion it gave me extra distance but only around 10' IIRC. That is usually not worth the extra variations in angles. for me it is nigh impossible to throw with the same form at high speeds where the extra D is a requirement. Former swimmer with no balance. Little power in balance muscles after having been supported by buoyancy i think. No need for coordination training in swimming.
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.