This question implies that Putin and his supporters—and fwiw, a lot of Russians who are not his supporters—have the same kind of Complex regarding other countries in Europe that they do with Ukraine. Or that the Russian military has any serious capability left for other misadventures.
I do indeed take your latter point - but the idea that Russia should restore the "glory days" and take pretty much the entire former Soviet/Tsarist empire back, is now a staple of state media.
Russian state media’s
job is to troll and promote deranged conspiracy theories. That doesn’t tell us much about what Putin is actually thinking or planning (but then again, little does—his is an infamously opaque regime and the circumstances leading up to the decision to start this war are still fairly unclear).
