What is the plow? Pictures of the plow, the setup, and an action pic of the results would help us tremendously.
Ballast isnt your problem. A 5000# 2wd UTILITY tractor with R1 tires should pull a 2-bottom plow with ease.
Your setup method isnt bad.....but using a 6x6 block (which is only 5.5"), and the tire will flex around it, and you have also not blocked the front tire.....you are basically setting the plow to cut SHALLOW. Like 4"
Whatever the bottom width....say if its a 14" plow....Ideally set BOTH the front and rear tires @7"......then adjust and manipulate the top and side link to have the plow shares LEVEL and FLAT.
Draft control not working shouldnt be causing you this much grief. Because setup properly...the plow should self regulate to an extent. For example.....when you raise the 3PH and lift the plow out of the ground.....notice the points pointing at a downward angle?......Now lower the plow to ~7" below grade and it is now level if you setup correctly right......Now any deeper than 7" and the points start pointing upward.....meaning if the plow tries to dive too deep, the geometry should level it back up at 7"
Now the trash issue.....
There are so many styles of plows and some handle trash better than others. Its not always a coulter setting. Without pics to see whats happening, hard to say. But some more modern plows have higher clearance beams, and trash/cover boards above the moldboard. They all help. The older style plows like the ford or dearborn plows wadded up above the moldboard with trash real bad, especially corn stubble. I fought it with my 3-14 plow. I switched to a higher clearance plow with trash boards.
But there is also a trick of using a piece of #9 wire about 8'-10' long, and tying around the coulter shaft and letting it trail in the furrow to help burry the trash and crop residue. So thats something for you to maybe google and experiment with
But Pictures Pictures Pictures. They will help us figure out whats going on better than any type of written description you can give us