The SD card reader does not initialize when in stand-alone mode and calling menu item 'Init. SD card'.
Expected behavior: A working SD card reader in both stand-alone mode (no USB connected) as well as in USB connected mode
Actual behavior:
If you are using (and sharing) the onboard SD card reader then the SD detect state really should make no difference (and never has done until now), as the SD detect pin is disabled in this case (see the pins file https://github.com/MarlinFirmware/Marlin/blob/bugfix-2.0.x/Marlin/src/pins/pins_BIGTREE_SKR_V1.3.h#L278). Are you sure that the change to SD_DETECT_INVERTING is actually required if the other settings you have changed are also made?
The default configuration for this board is to use the SD card reader that is part of many LCD displays. Personally I don't think that this is correct, but that is the way it currently is (and will probably not change), other LPC176x boards default to use the onboard reader (which I think is the most sensible default).
However if you are using a recent version of Marlin it seems that some recent changes to the way that the SD card is initialised may have broken the SD card sharing code... https://github.com/MarlinFirmware/Marlin/issues/14318 I'm about to start investigating what is happening in this case...