Sorry to sound like I'm talking down to you, but you understand that the battery pack is made up of modules of cells? Each module is shown separately on LEAFSpy, and the BMS works on them in pairs. You cannot "calibrate" the battery as such - the BMS does its best within the limitations of the cell pairs. What can be done,
BUT I AM NOT RECOMMENDING IT, is to split the case of the battery and access the individual cells. If you charge individual cells it is possible to get the voltages closer at the bottom end of their voltage range and hence delay the advent of the Turtle appearing (which is based on the lowest voltage of any cell).
You have not included a LEAFSpy image of the battery at present when it is fully (or as near as you ever get to fully) discharged. But if you imagine that this image you posted on the pack charged was it discharged:
If you look at module pairs 77/78 on the x-axis they are considerably lower than the others. If this was a discharged image then it is that pair that will cause the Turtle to appear first or just your GOM to indicate no range left. In theory charging just those cells up to the level of the others would increase the range of the pack as the other cells have further to go to reach the limit.
In practice there are many issues:
- Splitting the pack means working with very high voltage and danger of death.
- The modules are likely to be genuinely weak and will likely return to their lower readings quite quickly
- If they are weak they are likely to charge at a different rate limiting the full charge potential
You could replace one or more modules, but without a discharged image from LEAFSpy it is impossible to tell how many are required. My guess, and it is no more than that, is that it is more than 10 (most of the rear ones) and that a different battery pack secondhand from a cool climate such as the UK would be a more cost effective idea, although you are then into issues regarding reprogramming the car to accept the different pack.
So the next action has to be to run the battery as empty as you dare then get another LEAFSpy image and post it here. Good luck!