Russia's performance in Ukraine is more of an indication that Russia is a regional power with nuclear weapons rather than a great power - so it is to an extent two regional powers of dissimilar sizes duking it out but the smaller power has the support of multiple nearby regional powers - Ukraine has done amazing with what they had on hand and have received but without foreign support they'd be struggling much more.

There is currently one great power in the world and one very close to crossing the line (the US and China, EU could do it but realistically won't because of national identities).