The ‘new kid on the block’ is a reference to a country now openly challenging the U.S.
The cold war ended decades ago, Russian military strength and technology is increasing, not decreasing, it’s why they’re able to challenge, just like China.
The Ukraine is a battleground of competing dominance. Russia, v the European Union and the U.S. The EU and the U.S. were out manoeuvred by Russia and sent packing. That hurt and the response is sanctions and moving NATO closer to its borders. Russia is still there, the EU and the U.S. are not. The world is changing, it’s just something to get used to.