It’s complicated because it requires a new head, new damper, and new cleaning assembly all together. These items need to be registered and calibrated properly after the swap-out. Cost of repairing is generally about the same as a P6000. IMO I think you would be good to buy a P6000. Finger’s crossed we’ll have a cartridge solution for this printer by the time your first set of Epson carts runs out.
It would be different for the 9900 as the cost of repairing this printer is less than the cost of buying the new version (P9000).