Both Turkish and Syrian forces are slowly crushing their opponents. When Afrin and East Ghouta are taken, war in Syria will enter its next phase and it will be Americans and their allies in the SDF, that will have to make some hard choices.
Turkish operations against Kurdish forces in Afrin are entering their final stage. Turks and their allies in the FSA are only one kilometer from Afrin itself. Pounded by Turkish air power, besieged from all sides, with only a token support from some Syrian militias, Kurds are on their own and can't stand long against the second strongest NATO member. Not even reinforcements from other Kurdish controled areas in Syria can change that. It is only a matter of time, Kurds in Afrin have to make a decision to fight till the end, or evacuate across Syrian controled territory to the east. They will have to make that decision soon, if they don't want to end up in a pocket, to be then cleansed by advancing Turkish forces.
When the operation in Afrin is over, Turks will turn their focus to the east, to the city of Manbij and then they will come into conflict with Americans and their allies in the SDF, which is a predominantly Kurdish force.
Syrian forces have dealt heavy blows to rebels in East Ghouta, dividing their territory into three pockets, aftter allready conquering the entire east of the enclave. Fighting in more built up areas promises to be more chalenging and Syrian forces will want to negotitate some kind of a settlement, so to minimize civilian casualties and their own loses. Story of Aleppo could repeat itself, if rebels, pushed to the wall, take the offered way out and vacate East Ghouta for Idlib, taking only their personal weapons with them.
After East Ghouta is taken, Syrian government will have a choice to make, where to focus next and it could well be towards the east, bringing them into conflict with Americans at Al Tanf or across the Euphrates river with SDF.
US forces have in the past allready attacked Syrians attempting to close on them, sending a message, they wont relinquish their control over large parts of the country that easily. It will most likely happen again, if Syrian forces start a large scale offensive, but in that case, they will bring large forces into play, thus making life very hard for US air force in the region. On the other hand, if Turks start pounding SDF positions in eastern Syria, even endangering US troops, Washington will be hard pressed to retreat and leave Kurds to their fate. Consequences of a break with Turkey are to bad for US to even consider. Not only problems in the Middle East, but in the Eastern Mediteranean and the Black Sea as well. United States would lose an important ally, who in the past served as a bulwark against Russian influence.
Much depends on Russia. Syrian forces can only with huge losses advance against American air power and so they need Russian air support, but it is hard to see, based on everything that has happened so far, how Russians would be willing to risk a hot war with Americans. Because of that, it could well happen, Syrians could turn their attention to other remaining rebel pockets inside their territory, leaving the Turks to move freely in north and east. After all, Turks are allready destroying those forces, Americans relly on in Syria. Many Kurds have perished in the fighting and when the Turks move east, many more will. This way Syrian government is rid of a problematic clash with SDF, if they want to take the east under control. But, on the other hand it can all well end in a new partition, with Turkish troops controling large parts of the country. The only good thing for Syrians, Americans then wont be arround any more.