Is light quantized?

At the source, but it is matter that is packed at specific ratios. The Compton effect is fundamental, there is always a wave/mass relationship, either mass itself, or mass + wave kinetic energy, both quantize together.

Scientists say light maintains its frequency through free space because its energy is quantized and unchangable, except for red shit which is a frame problem.  But that theory assumes the impedance of free space is constant.

But the idea that an electron orbit determines the quant of a photon is hard to believe if you believe in unchangeable light quanta.  Why would a photon accept a particular form arbitrarily chosen, then keep that form?

Most of the explanation for the dual nature of light is simply explained by the source and destination of light in terms of energy quants, not necessarily intrinsic to light motion.
Einstein said:

Although he accepted the validity of Maxwell's theory, Einstein pointed out that many anomalous experiments could be explained if the energy of a Maxwellian light wave were localized into point-like quanta that move independently of one another, even if the wave itself is spread continuously over space.^[5] In 1909^[40] and 1916,^[42] Einstein showed that, if Planck's law of black-body radiation is accepted, the energy quanta must also carry momentum p=h/λ, making them full-fledged particles. 

Sure, but that assumed the vacuum itself is not quantized, a basic assumption Einstein made at one time. Then, as we saw, Einstein says the vacuum has energy, a quant of it. So, then free space cannot be a blank slate. Relativity does not explain the contradiction.

So the red shift theory says that these should not be considered quanta, and energy is conserved because the blue shift at the source and the redshift at the destination maintain energy. But if light is not quantized, then what happens to beam spread over distance?

The intensity (or illuminance or irradiance) of light or other linear waves radiating from a point source (energy per unit of area perpendicular to the source) is inversely proportional to the square of the distance from the source; so an object (of the same size) twice as far away, receives only one-quarter the energy (in the same time period).

Look long enough and you will collect enough energy to measure frequency, they say..

Then you have a conundrum, the impedance of space is everywhere a scalar but distance is not, and  time expansion has no effect on impedance?  That rules out space time expansion I would think.  Impedance can be a a vector, and still maintain the speed of light if one accepts that frequency changes.

It is the same conundrum Einstein reported with the vacuum noise, either it changes with spacetime or energy is created some how. And, if the vacuum has an energy quant then how is impedance everywhere constant, regardless of energy quant? Further more, if impedance is a scalar, then how can light have vector momentum?

What about Planks constant in space?

They imply that the rate of change of magnetic and electro is always constant, regardless of field strength of the light. Then that rules out the Plank's constant for the vacuum of space.

But wait, you say, the impedance has more time to be impedance as the frequency changes. Well that rules out the idea that impedance is a scalar, right?

But wait, you say.  The light itself holds the vector, but impedance is a scalar.  Hard to believe that light energy can contain a vector but relies on space to maintain impedance, regardless of direction or frequency.

No where is there any metion of space time expansions effect on the impedance of space. Yet, here we have gravity, a vector with a constant value relative to local energy.  It warpds space time but leaves impedance alone? How nice.