The decline of Russia means the Rise of New Ottoman Turkey.
A new baddie always replaces the last baddie.
“The decline of Russia means the Rise of New Ottoman Turkey.”
It would definitely help Turkish power to rise relative to Russia, but Erdogan may squander the opportunity with his own poor economic policies and corruption. Inflation in Turkey was still running hot at 38.2% in June 2023 (down from a peak of around 85% last year), because of Erdogan’s excessive money printing.
Oil and gas flows out of the Black Sea are a big prize up for grabs in this war. Whoever comes away with them will be stronger for it.
As much as they would like to, Turkey has no ability to expand in the north/west. In the east. Georgia and Azerbaijan would probably ally with Turkey, and Armenia would be easy pickings. Maybe Russia's Caucuses declare independence or even side with Turkey depending on which way the wind blows, but that's about as far as it could go. Beyond that, Russia would probably use nukes to defend their sovereign territory. Syria would fall, and Europe would get the pipelines from the Middle East that Russia has been blocking.
But Russia still has huge oil and gas reserves. A "declined" Russia just looks like a more corrupt Saudi Arabia. Now if the Eastern republics free themselves, say east of the Urals, then Muscovy becomes North Korea. But that only happens if China backs them, and at that point, the old saying "why buy the cow when the milk is free" applies. China will already control Russia.