Without knowing a great deal of the graphs the usual answer is: Strip, clean and rebuild. Dec axis on the HEQ6 and EQ6 and I expect the EQ5 is kind of well known to be weak.
Many will replace the bearings, certainly the stuff Skywatcher call grease.
Be careful of the small weird cone at the end, that takes some setting up correctly.
Took me 3 attempts, the first 2 were working out what was going on. Getting the grub screws in was "entertaining" to say the least.
Search out "astro baby" and see if she has a guide for the EQ5. Half suspect not as Mel did the HEQ5 and EQ6.
Might find the UK SGL forum has greater experience, knowledge as the miount has been around the UK for some years and is popular.
But Dec axis and Skywatcher are not a great combination. Especially that goo.