I enabled the laser by writing 0x00 (or 0x80) to LASER_CTRL0 (0x20).

Since LASER_NEN is low and bit0 (Force_Disabled) of address LASER_CTRL0 is zero, I guess your laser is indeed enabled.

Maybe there are problems with the navigation of the sensor

In data sheet, the addresses 0x21-0x23 are reserved. Maybe you should not read from these addresses ( I don't know whether it helps, but it's worth giving a try )

You can also check whether SROM code is running by checking Observation address (0x24), bit6 should be equal to 1 if SROM code is running

good luck!