print the diagnostic image from the maintenance menu, and see what it looks like
next, as kyle advised, weigh the printhead on some kitchen scales. 60g is a full printhead low 50's likely means there is air in there.
an empty printhead is around 48 - 49g so in theory its about 5g of ink (x2 for each colour)
So this means, if your printhead is reading 53g you dont know if thats an equal amount of ink or one chamber could be full and the other side empty.
I got a primer / refill tool from these guys:
https://www.inkowl.com/inkjet/ink-refill-tools/hp/printhead-repair-tool-for-hp-70-72-73-88-91-761-762-771-773-774-940/P5035/LPS also do one - I dont know where you are located so depends on your closest place.
That will suck the air out of the printhead and draw in fresh ink from a funnel. Works ok, only it draws in both sides at the same time, so dont just fill up one ink.
that what I used to bring my printheads back to life.
One thing to note as Kyle has already said - if its been printing air not ink, then the printhead will likely be shot as that burns it out - but its certainly worth a try.
personally, I think I would just get a compatable printhead and save myself the faff of priming - it can be messy