There won’t be any peace in Syria as long as Erdogan has his forces there.....and since he’s too invested now he’s not going to back down...He wants to put his own people in power in Syria if there’s any way he can obtain that.
The Syrian war could not exist without the Turkey/Syrian border ....and Turkey is ‘still’ supplying Alqueda with weapons, just as he let Isis and the other terrorists pass through his borders..... who are now fighting with Erdogans troops and doing joint attacks and patrols together against ‘Afrin” and the KURDS.....
I agree with your assessment on all points, except that I think it might be possible for Turkey to annex some territory in a final settlement.
Despite that possible reservation, I think your assessment of no peace while Turkey remains is more likely, especially in Afrin. It would likely require an epic genocidal ethnic cleansing to enable Turkey to fully pacify Afrin.