Output of G29 bed leveling, Marlin 2.0
Actually the sensor reads the bed correctly in terms of shape, not in actual reproducible distance.
Plotting the grids:


Results in pretty much the same shapes, so, when correcting for the maximum displacement and plotting all results in a single graph gives:

So the sensor does seem to produce reproducible bed geometry, but not the actual values.
Misinterpreting your initial question I assumed a default Anet sensor, this  official ROKO SN04-N sensor is reported to not be very accurate and has a maximum hysteresis of 10 % error of the detecting distance, which is 10 % of 5 mm (so ± 0.5 mm). The overall maximum measurement is in grid 4 with a value of 0.949 mm and in grid 1 with a value of 0.124 mm;  0.949 mm - 0.124 mm = 0.825 mm is well within the ± 0.5 mm. This seems odd as the hysteresis should be in play on all measurements as the probe goes up and down. I've used this sensor myself, but replaced it for a more reliable sensor like the LJ18A3-8-Z/BX.
Now that it is clear that an accurate sensor is being used, there might be some play/backlash present in your printer. You should check the probe mount and the Z-axis.