A space chief as a military strategist?

You're forgetting that Russian generals are demoted if they win too much, since they could become a threat to Putin's position if they gain too much influence.

There's no way to win in the Russian military, other than the bribes in your pocket.

"USSR logic"

Most probably he will not be a military strategist, but something like governor whose task will be reintegrating these territories in Russia.

He has a great experience running Roscosmos which is quite a large corporation.

And he is very patriotic, highly motivated, will not sell or betray Russia. That's why he is ideal for that task.