I want to do something to help you buddy. Because you are so cool. I have been studying your multi material benchy and it's blobs and I think I know something that Will help. Linear advance or lin_advance is a way to tune for pressure in the nozzle. In theory a perfectly calibrated lin_advance would need little to no retraction. With long PTFE tubes and in line switches/merge points between the driven gear of the extruder and the nozzle your machine would most certainly benefit from enabling and calibrating this setting. I follow this tutorial for that.. https://www.youtube.com/watch?v=n3yK0lJ8TWM&t=