

Take as much Novgorod land as you can manage, focusing on the core required to form Russia, and border provinces with Sweden to prevent them from swiping in.

You wanna do this fast because your AE will allow your neighbours to get allies. With your vassals in tow you should be bigger than them, as long as they don't get any major allies (which they usually don't because Orthodox). Novgorod has control of the North Sea trade node, which is where all your money is leaking out of, and they are your local rival. Your opening move should be to take down Novgorod. I played Russia on 1.24, so this might be slightly outdated, but it should be good enough.
