Lighting System in terms of its efficiency and consumption
The brighter the lamp, the higher the magnitude of luxes.

Depends on your definition of &quot;brighter&quot;...
1 lux = 1 lumen / m2
Say you want to light your desk. Same lamp at different distance from desk will produce different lux on your desk. Power decreases with square of distance, so double distance, divide the lux on your desk by 4. And if you put a mirror behind the lamp, or other kind of optics to direct the light, then you can direct more light where it is useful. So you get more lux, but the lamp is still the same.

Does the higher the neutral current, the more it consumes energy ?

That's only valid for resistors, and your lamp is not a resistor.

But what indicates the value of real power, reactive power, apparent power and power factor ?

&quot;Apparent&quot; power means you take the numbers on the ammeter, the numbers on the voltmeter, and you multiply them, so you get something that looks like a power, but it isn't meaningful except to check the rating of breakers and wires. Likewise for current alone.
Read the details.
Active (real) power is the one that counts, and it's what you pay for on the electricity bill. If you want to measure the efficiency of a lamp, or the how much light it puts out per watt of input power, then you have to use real power.