1) Kurdish forces in northeastern Syria would be well advised to strike a deal with the authorities in Damascus while they can still get one. Neither Syria nor Turkey has any interest in seeing an autonomous Kurdish-led administration emerge in the region.
2) Syrian & Turkish interests will eventually converge on this issue after Idlib. The US will in the end leave Syria when they realize the price isn't worth the fight. History has borne witness to this fact several times, such as in Lebanon in the 1980s & in Iraq more recently.
3) Even though Syria is strategically and geographically important to the US in its current efforts to weaken both Russia and Iran, they will eventually realize, if they haven't already, that the cost is too high and that it would be better to strike a face-saving deal to leave.
4) Israel already faced this situation in southwestern Syria. The Israelis realized that their agenda failed and that they would rather have Syrian army forces on their border rather than Iranian-allied ones and so they gave up and sold out the armed groups they were sponsoring.
5) The US has a consistent record of selling out its allies when they no longer serve a purpose so Kurdish authorities shouldn't hold out much hope. The Kurdish self-administration project in northeastern Syria is temporary and they should realize this point.
6) The recipe of a Syrian-Turkish alignment of interests vis-a-vis Kurdish autonomy, which they will not be able to resist, and an eventual US withdrawal will leave Kurdish forces with no options whatsoever. Their best bet is on an immediate deal with Damascus.
