Comparing intensity of colour in coordination compounds

Question

I had given an examination recently in which the question asked was:

Write the decreasing order for the intensity of color in $\ce{[CoCl4]^{2-}}$, $\ce{[Co(CN)4]^2-}$, $\ce{[Co(H2O)6]^2+}$

What my approach was to first find out the geometry of compounds after which I found the geometry as follows
$\ce{[CoCl4]^{2-}}$ : $\mathrm{sp^3}$,
$\ce{[Co(CN)4]^2-}$ : $\mathrm{dsp^2}$,
$\ce{[Co(H2O)6]^2+}$ : $\mathrm{sp^3d^2}$

Now, I approached the question with the thought that more the symmetry less is the intensity of the color of the compound, which gave me a conclusion about what I had learned earlier that intensity of color in $\mathrm{sp^3 > sp^3d^2}$. And as the symmetry of $\mathrm{dsp^2}$ is comparable to that of $\mathrm{sp^3d^2}$, in that the intensity of color would be more for strong field ligand.

This made me conclude to the answer $\ce{[CoCl_{4}]^{2-}$ > $[Co(CN)_{4}]^{2-}$ > $[Co(H2O)_{6}]^{2+}}$.

But I am really confused and not sure about this answer as maybe the intensity of the color is completely determined only by the nature of the ligand, or geometry is involved or not. I also have confusion about how should I compare the intensity of color in $\mathrm{dsp^2}$ and $\mathrm{sp^3d^2}$.

P.S.: If possible please answer the question with basics as I am a High School student and don't know much about Higher Chemistry.