So I had issues with BBA for months and never got it under control. Ended up having to do a new tank with mostly new items.
I had soil in the bottom of the tank and I think that was helping it to grow too rapidly to the point where the shrimp couldn't manage it.
When I set up the new tank, I did smooth pebble stones for the bottom and put the soil in clay pots to keep my plants in. I have not had any issues since doing this!