We'll see what others have to say but my thinking from reading your post is your on the RR too much not the LR.
Just IMHO now but if your on the LR and can't get off it you will likely/probably be able to turn in but after that it won't want to turn or complete getting you around the turn.
Again just IMHO if it's the RR your on with a ton of weight all the time that's when it just wants to go straight at the end of the straight.
Another thing which I think can make it want to go straight at the end of the straight is chopping off the corner on entry. Chopping off the corner is when you get down low into the corner pointing more straight and you simply can't make it turn enough to get into the corner. Chopping off the corner is about not being able to complete enough of the total turning you must do early on enough in a turn.
And that's all just my thoughts. With your question and what you already gave us i'm sure you'll get help.
I'm sure all would also like to know how much stagger you have now and how much banking, even maybe letting us know the track or maybe a Google Earth so we can see the track. I've found if you look at the track on Google maps/earth many times you can see the line most run. From that you may be able to tell if your running the same line others do on entry? A lot of times new racers sort of force themselves to chop off corners on entry trying to stay out of the way. That's good to get you comfortable with what your sitting on at first but sooner or later you have to take the part of the track which needs taken by all to get around ok.