Several posts on this forum ask the question about the role of amplitude in calculating the energy of an Em wave. This struck me as odd since I learned that E=hv. There is no amplitude in the Planck relation. But I see why this might arise as a question since every other description of waves includes the amplitude in energy calculation. This posts on this forum highlight the question:

The energy of an electromagnetic wave

Energy in an EM wave should depend on frequency

Where is the amplitude of electromagnetic waves in the equation of energy of e/m waves?

In one post I read that 'The macroscopic electric field of a wave consisting of photons does have an amplitude which is statistically built up from the individual photons.' My interpretation of the answers in these posts is that the photon is a fundamental unit with a fixed amplitude. In the same way that the speed of light is a fixed velocity, it appears that the amplitude of a photon is also fixed. So this leads to the question of what is the amplitude of a photon

Amplitude of an electromagnetic wave containing a single photon

I cant seem to determine whether the question was actually answered in that post. But why is it not valid to just use the fact that in a wave, energy is proportional to amplitude squared

Why is energy in a wave proportional to amplitude squared?

E=hv

E~A^2

so the amplitude of a photon should be

a~(hv)^1/2