What are the rules you have to use for the polygon division? Without rules, an automated solution will not be possible. And if you only have hundreds to do, a manual solution would be faster if the rules are many, complicated and/or there are exceptions
That is what I am asking you. I see no obvious set of rules to apply.
Your horizonal division appears to be parallel to the top boundary of the area, but the top is not a straight line so you would have to generalize the top.
If you wanted to use the bottom, then there is no rule of logic to make it useful
There is always the left boundary, but the vertical lines only are parallel to it for a bit, then they begin to change orientation.
So in short It is far more likely that the human eye could subdivide it up into appropriate lot shapes... that would leave the fiddlybits of making sure the areas were of a minimum / appropriate size and other details. That's when you would hand the project over to your technical assistant once the conceptionalization is done Good luck