No way I can assist further with a black channel that prints in that manner. I know only of a head replacement. Others will do head soaks, run cleaning solvent through that head, etch. That there could be your primary issue.
Your print test actually looks worse after the parts replacements. You have fuzzy lines now where you didn't in the first few pics. By chance did you raise the printhead to high when replacing parts. Check in the printer menu.
I haven’t changed anything. I did notice the head is on the low setting.
Thats good. That should only be moved if printing thick materials. Did you replace the tops with the felt backed ones ? The rubber backed ones have been known to cause problems.