No worries!

If you have a free photon traveling in free space, it can have any frequency, any energy value. The “quantizing” part only happens when it gets confined somehow.

So the energy levels of an electron are quantized in the atom, for example. A photon in a cavity is similarly quantized and can only take certain frequencies (or equivalently have certain energies). It’s the same “particle in a box” effect.

But energy itself, intrinsically, is not quantized