97 Chevy Blazer rear drum brake issues (grabbing)

I own a 1997 Chevy Blazer 2-door base model with the 4.3L and rear drum brakes. I have been having issues with the rear drum brakes grabbing and hanging up since about 6 months after I purchased it used two years ago. The issue occurs about 50 miles of driving after cleaning the dust out of the rear drum brakes. The brakes will make a high pitch squeal from the driver rear wheel when stopping from a low speed or a drift and the rear wheels skid/lock up at first until the ABS kicks in and then you can feel the ABS counter acting the locked up wheel. Sometimes the feel like the stick on when I go to pull away from a traffic light and make a clunk when the release. The brakes feel grabby and it’s hard to make a quick stop when they are acting up like this because of the ABS kicking in to counter act the wheels locking up. Also feels like the one side (rear driver side) grabs more and release last when letting go of the brake pedal from a stop. The vehicle feels like and uneven release of the brakes.

So far I have replaced with brake spring hardware, brake shoes with a higher quality pair from Napa, drums, wheel cylinders, cleaned and smoothed the backing plate, A new ¼” brake line from the ABS module by the master cylinder back to the hose at the axle and new 3/16” lines across the axle, new brake hose, new brake fluid, the rear axle seals where replaced and are NOT leaking and adjusted the e-brake cable. Yes the shoes are installed properly, the bigger shoe on the back side. I have not replaced the self adjusters but they spin freely and are clean.
I am at a loss of what to do. The issue has gotten me really annoyed. I feel that someone out there should have come across this. If you clean the brakes to remove brake dust the issue goes away for about 50 miles of driving. I have even tried to adjust the shoes in away from the drums a bit per a mechanic I know and the issue still came back one brake dust accumulates. Seems like too much stopping from rear? Someone mentioned a proportioning valve. Where is it located and what kind of cost am I looking at for this now? Thank you in advance!

I have checked and re-checked everything is installed properly. Here is a picture of what my configuration looks like. This is not an actual picture of my brakes but a picture I found online. Thanks.