Great explanation!
My bed is now ±.2ish mm off over the whole surface. Not too bad in my opinion.
I re-did the bed tramming yesterday and double checked the nose distance to the bed in all 4 corners of the bed. And unfortunately, I found out that the gantry is racked. Nozzle distance is in 3 corners the same, but I have +1mm in the back left corner. Means Y is in the front is either -1mm or in the back +1mm.
Don’t know if I can anyhow fix this - would be an easy task on a Voron or any similar built printer.
In the meantime I am certain that Bambu Lab is and was fully aware of these issues and this is the reason that they do not provide any bed mesh information to us users anywhere in the fancy UI‘s and I am certain this is why they fully encrypt all the log files. I am very disappointed.
Bambu Lab! Start a honest communication about QC issues and stop sending people through a fucking hassle support process when things are clear and obvious off! It starts to feel like a scam!!!