I have an Ender 6 with BL Touch which, apart from a few minor tweaking in the early days, has provided very good prints.
A few weeks ago, a friend asked me to print out a battery cover and it looked a bit of a mess. I was able to clean it up manually and he was happy with it but every print since then has been a mess and I have tried every suggestion I could find without success. Despite this happening without any changes to my Cura settings, I have tried making adjustments. I have recalibrated BL Touch several times and installed a new nozzle. I've tried lowering the extrusion temperature and raising it - any difference is unnoticeable. The nozzle size is set correctly in Cura and the layer height is 0.2mm. Everything on the printer feels secure and solid.
All my previous prints would have a near mirror finish on the bottom when removed but now, there are gaps of varying widths between print lines. layers are uneven and although I usually have ironing enabled, it isn't happening properly or when it does, the surface looks quite uneven (the enclosed photo is without ironing to show the infill.
I should point out that I added a PEI bed and silicone buffers which I had ordered before the problems started and installed afterwards - they have not affected anything one way or another. Also, I am mainly using Cura v 4.8.0 on a Mac Mini to preserve the environment which last produced good prints but have the same problem when using Cura v 4.13.1 on a MacBook Pro.
The enclosed photo shows most of the problems. This is a typical print exactly as it appears - along with all the debris. I ensure that the nozzle has no material dangling from it before a print starts but excess seems to get deposited all over the place.
I'd be grateful for any advice as I have practically had to give up trying to make anything of any quality.