You are at a disadvantage in trying to troubleshoot an old printer with old inks which you are uncertain about for a process that requires exactitude.
From the test target print it is clear (as long as you are following our Gamma 2.20 workflow) that the inks are definitely not sorted correctly.
Where you should start in troubleshooting this is printing the Calibration Mode target in Calibration Mode. That will separate out the 7 ink channels. Visually we can tell a lot about what's going on from the Calibration Mode printout.
1) Please print it once with the printer as is. You should see seven distinctly different ink shades. Of course in Calibration mode each shade will print in 21 steps - so look at each of the ink strips and see if they are actually seven different shades of ink printing. Post it here will be helpful.
2) If several look similar to each other - please remove all of the ink cartridges and shake them gently for about 15 seconds and return them to the printer. Then run 3 POWER CLEANS or initiate the INITIAL INK FILL to move the shaken ink in the cartridge through the ink lines and ink dampers into the print head. Now repeat the Calibration Mode target and see if the system is improved. Please post that picture here.
If you have an Eye1 to measure - you can measure the L value for the 60% patch of each of the 7 ink shades and jot that above each 60% patch when you post the images. We can tell you definitively from that!
If the system is not sound - then you will need to start this printer off with fresh inks. Either your inks are too old, or they have been allowed to print over time without ever shaking and are now too heavily pigmented, or they have been cross filled and therefore contaminated. Ultimately, the inks need to be in peak condition for this process to work!