Wouldn't it make sense to have the printer save the z offset? It gets “lost” between RESTARTs and power cycling.

For various different reasons the value isn't a consistent single value worth saving:

• varies by filament

• varies by initial layer height

• if using with an uncalibrated probe and so including an error adjustment value this won't be a consistent value with saving because of the changing error adjustment.

The gcode z offset is never saved under Klipper nor does that make sense. It’s supposed used for fine adjustment of filament squish to assure non-tangential bonding of extrusions to adjacent layers and walls.

If your gcode z offset is negative then you’re mid-using it to include an error adjustment for not having your z probe calibrated. This then leads to an inappropriate workflow that makes you think you should be saving it in order to keep accounting for the error adjustment from being uncalibrated .

What you want is to calibrate your z probe so you don’t need to keep the error adjustment value overloading the gcode z offset from it not being calibrated.

You can read how to calibrate your z probe on the klipper docs stored on your printer or online at https://www.klipper3d.org/Probe_Calibrate.html

Be aware that in later Elegoo software updates they broke this and other key klipper features purposefully, so you’ll need to manually edit the probe offset value to printer.cfg.