As I understand only the splines need to be greased. This is where the clutch disk rides. As Flaco mentioned, do not grease the area where the throw out bearing rides on.
That slave cylinder should not look like that, someone took it apart. I read through some of your earlier posts again and don’t understand the non sense about 330kph or which gear positions sensor you have on the block. You can’t just swap those parts, they are calibrated to the block (and piston), it may be that you or someone else did exactly that and that’s why the car doesn’t know if it’s in 1/R.
I still didn't didn't replace or exchange any of the actuating block component, because i already read that it is not recommended and initialy I don't want to. I have a spare block was laying in the trunk of the car when I bought it, That was the original idea of solving the issue by replacing the gear position sensor and it's harness, even though they repaired the wires. I will also remove that electrical tape and re-do it with heat shrink whenI confirm the sensor is working. That's what I am going to do next holding the block under the car and hook the connector to the car wiring loom and move the pistons by hand and check on ISTA the reading. In INPA it will tell you what is the current value and what is the expected value when the gear shift, and I already have a pictures of the previous test numbers.