It is not clear to me what, if anything, the Russians and Sultan Tayyip have agreed on. The battle east of Aleppo City out on the green plains of the fertile crescent seems a muddle. I don't see evidence of Russian participation, for or against the Turkish invasion of north Syria.
The offended party in the muddle, other than the Kurds themselves, seems to the US. Joe Biden was treated like a dog by Erdogan, and rose to the occasion by licking his master's hand and attempting to order what he evidently thought were other (Kurdish) dogs back to their kennel east of the Euphrates. It seems that the public example from Havana and Riyadh of how to deal with the Obamanites was absorbed at the renovated Sublime Porte. And now Obama plans to meet with Erdogan privately? He plans to do what, talk him down out of the tree? Obama is a city boy. He will find that this quarry has the measure of him.
The Russians are a different matter. They threw Erdogan a bone in lifting Russian tourism restrictions on people who want to go to Turkey. If they try to pressure Russia by not honoring the Montreux Convention on passage of the straits, they risk war with their northern neighbor. If they send their own forces into NW Syria they risk war with the Russian expeditionary force fighting as part of R+6. If they keep sending their surrogates into Idlib Province to be chopped up by R+6 they weaken their hand generally in the Syria struggle.
OTOH, if they seem to cooperate with Russia, the potential gains could be great even if their promises are false.
The sausage making machine at the SW corner of Aleppo City grinds on. If I were in command there I would want to continue that for a while until I estimated that exhaustion of means and will had set in on the unicorn/jihadi side. At that point I would go over to the offensive and pursue, pursue, pursue ...
At the same time, the unicorn/jihadi position seems to be collapsing around Damascus. Interesting. pl