At the end of the day, unless the U.S. makes a decision to set up permanent shop in Northeastern Syria, the region will eventually be controlled again by Assad, or it is going to be controlled by Turkey.
The U.S. media, with its unserious treatment of the true situation in the ME, likes to make it sound like the SDF has some chance to eventually hold this territory as a result of their military might combined with some brokered agreement between either the SDF and Turkey or the SDF and Assad. That idea is bullshit. The Kurds have no hand to play here. Yes, they are scrappy and resourceful fighters, but they are no match for Turkey and Turkey is not going to allow an independent Kurdish region to exist there.
They have not been engaging in conflict with Assad's SAA for a reason...and that reason is because the two sides have been negotiating under the radar for years now. The Kurds were offered more autonomy than they had before by Assad back in 2016 or so,, but they insisted on de facto independence and would not budge on their demand to keep the SDF as an independent military force as a prerequisite for coming back into Assad's fold. That was a non-starter for Damascus, which if one looks at it objectively, is understandable (what legitimate state could tolerate a separate military operating within its borders) and now the Kurds will likely cut a deal again with Assad, but this time, without even the other provisions relating to autonomy that Assad had agreed to before.
And if the situation presented itself to ally with the U.S. again in some mid-east conflict, the Kurds will just as quickly do it once again. This isn't about them wanting to die alongside us as allies because of shared beliefs or something...this is about choosing to work with the only "friend" they'll ever have with any influence (us) in the region to help achieve their intense desire for an independent Kurdish statelet. It's been going on forever and it will continue to go on.
This isn't new. Hell, Kissinger said in 1975: "Promise them (the Kurds) anything, give them what they get, and fuck 'em if they can't take a joke."
That doesn't make what our orange dumbfuck in the Oval Office did justifiable in any way. Rather this has basically been U.S. government policy for over 40 years and at some point, the Kurds/SDF needs to deal with the powers in the ME without some silly fantasy of them getting their own state. It just isn't going to happen and they need to negotiate with that in mind.