Russia’s military intervention in Syria has changed the entire dynamic of the conflict, bolstering the Asad regime and ensuring that no resolution to the conflict is possible without Moscow’s agreement.
Yes, Russia's intervention was decisive in ending the growing Assad defeat. Assad hasn't won, mind you. But he didn't lose back then, which seemed increasingly likely prior to Russia's late 2015 intervention.
But I strongly disagree with the idea that Russia has guaranteed that no resolution is possible without their agreement.
Bleed Russia enough financially and militarily to sustain their intervention and Russia will abandon their effort and lose the ability to grant agreement to the outcome.
How on Earth is it possible to concede Russia only advantages from their intervention rather than seek to make Russia pay a price for their intervention and make it a losing adventure?