Regarding your Print test result. Seeing as your print test just above is slightly worse on black, I am guessing you are already doing head cleans on that ink/head group? if so, it looks like it’s improving it?
the nozzles all appear to be firing but very light grey?
I haven’t had my Roland printers in years, so doing this from memory, maybe also check the damper filter on the blackheads isn’t holding any ink gunk on it, which may starve the head of ink.
or check there isn’t any air in the visible air-lines?
I know these machines have changed a lot since when I had them, so I’m hoping it’s still a similar setup.
if your shutting it down for the night/day leave the heads soaking, then proceed to do a head clean the next morning and see if that clears it.