Why does methane have 4-different bond dissociation energies? I will elaborate on my question here.
In my Lecture Notes it is mentioned that for methane, there are 4 different $\text{C-H}$ bond energies. I plotted a quick graph of the bond energies to analyse the trend.

Here the vertical axis represents the bond dissociation energy while the horizontal axis represents the bond dissociation number. Looking at the graph, there is no clear trend so I decided to turn my attention to the structure.
$\text{CH$_4$}$ has the following structure

It is from here that I am unable to proceed. Here are my questions.

Am I barking up the wrong tree by looking at the structure and how do I account for the changing bond energies
Is there a VSEPR structure for molecules like $\text{CH$_3$}$ $\text{CH$_2$}$ $\text{CH}$? If so how do I figure it out.
Why am I even learning about bond energies in the first place? Is there a way I can link this to a bigger picture? I find this topic very interesting and I want to tie up my knowledge neatly here.
Bond energies are important, but you have to start somewhere. Actually, I'm surprised that the bond energies for the four dissociations are so similar. But that's a good start.
Now let's get into a bit more interesting compound: ethane. Very interesting!

The table is only part of the information on ethane given in an open access article (Ref 1). Note that the first C-H bond dissociation requires 422 kJ/mol, while the second requires 150 to 465 kJ/mol, depending on which bond you are breaking, because of what product you are making. Each line in the table is worth several paragraphs of explanation.
I admire your desire to tie up your knowledge neatly here - get a lot of string, because it's a very big package!
Ref 1. https://pubs.acs.org/doi/pdf/10.1021/acs.jpca.5b01346   Branko Ruscic, J. Phys. Chem. A 2015, 119, 28, 7810–7837