I haven’t seen this mentioned anywhere, but I think it’s worth considering.
Historically, when Ukraine was ruled by Russia, it was considered “the breadbasket of Russia.” If Ukraine had a bad harvest, people all over Russia starved.
Of Ukraine’s top five exports, three of them are food.
So Putin invading Russia could be because he wants to secure his food supply. He’s worried he can’t feed his people, otherwise.
If so, it’s an expression of incredible insecurity on his part, not just flexing his steely authoritarian will.
Anyway. It’s just a thought.