The latest (largely ignored ) news is that Russia is now saying what I have been calling for over the last 4 or 5 years. That is a Syrian (only) negotiating table with UN facilitation.
https://sana.sy/en/?p=156231An underlying thought, also shared by some US analysts is that empowerment of the Syrians, by implication, weakens the respective hands of Iran and Turkey.
Presumably it is not in Russia's interests to witness an SDF/Turkish war in the North that leads to total destruction and further annexation of Syrian territory by Turkey. My guess is that Russian interest don't extend to a Turkish - Iranian conflict either.
Whether Iran behaves or not depends on the faction you talk to. There are both extremists and pragmatists in their midst. At the end of the day though the Iranian economy cannot afford ongoing conflict. Iranian pragmatists would know that Assad cannot control large swathes of predominantly Sunni territory in the North and that the Kurdish alliance with many Sunni Arab tribes there could become a longer term asset
in the wake of Trump's betrayal of these loyal allies. Iran does not have to do anything to gain influence with the SDF but stronger Syrian nation won't be an Iranian vassal either.
Assad is both a puppet and an idiot these days but his team can be guided towards constitutional discussion table with the autonomous administration in the North. Constitutional talks are an open ended process, not a military ultimatum.
I'm not betting on any near term outcome and actions need to quickly follow words. Backflips are expected in this space and if it's a ruse we will soon know.