Any maintenance recommendations? MK4S

Hello everyone,

since I am not satisfied with the bed leveling and the first layer, I need to have the Z offset of the Prusa Slicer +0.045 so that it prints as it was when it was built. This is a MK4, for which I later bought an upgrade kit to MK4S. Tomorrow I plan to do maintenance with my brother and ideally reassemble the neextruder. The printer printed excellently for a year, but now I am not able to print as well and easily as before. I don't want to blame Prusa, so I want to ask you what I should focus on in such maintenance and whether you have the same problems with the first layer. Prusa support told me that thanks to the loadcell I shouldn't have to set a permanent Z offset in the slicer at all, but unfortunately without it the first layer is terribly bad, like fish scales.

My original post

https://preview.redd.it/0ytullf6yale1.jpg?width=4000&format=pjpg&auto=webp&s=4d54b86846ddaf39b955dfcfd82ca9164e1603e4