The SDF organization is a CIA creation. You can't outsmart the Americans on it. It's their baby. It's non sense to say Russia could have been allied to the "SDF". You can't ally to something run by american assets.
The muscle within that structure, that is the PKK, which for all intents and purposes is what matters was indeed handled poorly by Russia in my opinion.
Russia was, more likely, presented with 3 choices:
1. Directly target the PKK (branding them terrorist/separatist from the get-go and bunching them with ISIS and Al-Qaeda). This would have required a larger military commitment from Russia, and it would have added more enemy fronts to the war. This would also inadvertently have helped Turkey, one of the main conspirators of the war, and the literal lifeblood of the uprising, for FREE.
This option was not taken. There are gray areas here that could have been exploited if Russia was cunning enough but didn't. Not gonna get into it.
2. Try to negotiate with them and offer support - material support, and protection to their cause - not just words. This would be contrarian to supporting Assad, elevating the PKK's separatism and its personalities, and thus undermining the territorial integrity of Syria. Neither Assad nor the Iranians would have accepted that. This would also strengthen the Turkish/Arab/American axis on their commitment to the war by taking out areas of friction between them. All the white opening areas of friction between Russia and its allies. Simply a non-starter.
3. Keep contacts and mostly "ignore them" - rope-a-dope. This option has the caveat of knowing well that this would leave a vacuum of power that could only be filled (and was indeed quickly filled) by the Americans. The doubt however, at the time, was that the Americans MAYBE will NOT fill this vacuum, DARE they sideline its NATO ally Turkey.
That was answered, and the de-facto side-effect it has is the strangling of relations between Turkey and the U.S. Thus pitting two allies against each other.
This allowed the U.S however to cement its position in the conflict with a palatable proxy force to excuse its invasion of Syria - annexing 1/3 of it. The Americans obviously understood the gamble well, and are trying to come out of this betrayal to Turkey unscathed. That is obviously becoming a bit of a pickle. The Turks have been completely had for the most part given what the Americans have done to them. Fuck Erdogan the fool for setting fire to his neighborhood - serves that Muslim brotherhood cunt well that he caught fire himself
Russians knew this very well - despite acting dumb on the topic and hoping the Americans wouldn't do what was given to them on a silver platter. The Turkey "split" is recompense to Russia however. For Syria on the other hand, not much consolation for losing 1/3 of your territory. But outside of Russia who will help them? Iran could only do such much vs. so many foes. So the Syrians play the game.
Russia took choice #3.My choice:
Try to negotiate with them early on in the intervention to come to a reasonable accommodation that didn't involve federalization or autonomy. Assess the level of infiltration and flirting that this group had with the Americans - to plan the map of operations if the American alliance was in the works (cutting them off Iraq would have been key). If that wasn't possible, at no further than after the Aleppo operation (or close to the transition of power in the U.S), switch gears and target them militarily, with a ruthless well coordinated campaign, with the propaganda machine ready to go, with clear overtures to Turkey all in between and at the least box them to just North Syria.
I think Russia made a grave mistake when on the eve of the rush to Deir-zor, it came to the deal with the Americans for the demarcation of the Euphrates river - shouldn't have agreed that far South, including all the oil fields. Despite whatever side-effect it had with Turkey it wasn't worth it.
The Americans aren't budging (unless they get Syrian Kurdistan ala Iraqi Kurdistan), and neither Assad nor Iran are willing to part ways with 1/3 of Syria just cause Russia is fine with it. The Turks were betrayed but they don't dare anger its master of 70+ years besides some barking (flirting w/ Russia, the S-400, SCO, Venezuela etc). Thus we got the freeze. Unless of course Turkey goes in on the PKK regardless of the Americans... then the fireworks can truly begin.
The PKK is not a party you negotiate with - it's a party you disband and destroy, sending them to the 7 seas. They will not negotiate its demise with Assad and the government of Syria, the very one they're trying to split away from. It's nonsensical and contradictory but propaganda does a helluva job on the uninformed. They have shown they will ally themselves with the devil, as long as it pushes their separatist agenda.