I read an incredibly thorough book about Putin a year or so ago, and what stuck with me is how political his career in the KGB was. In those final years of the USSR, everything was in shambles, and any position of power became so through-and-through political. That makes his rise so interesting and frightening. He has been forged in a dark web of covert slush funds, power projection and kompramat. He was obviously ve…
there's also long interviews from 2017~ on PBS Frontline IIRC, a series called "Putin files" Julia Ioffe, Masha Gessen It's partial but has a lot of detail On the other side there are the Russian friendly views such as Mearsheimer or even Stone. It's difficult to weigh what is true (even though I'm biased anti aggressor in this case)
I don't know that I would refer to Professor Mearsheimer's view as pro-Russian, he has plenty of criticism of Putin and the Russian political system in general. But the fact that he has been railing on the likely consequences of our approach for dealing with the Russia/Ukraine situation for years, and been proved right, should make his writing and interviews required for anybody seeking to better understand who we got here.