The fall of Avdiika could have been thought of in two ways. From an offensive perspective it was a disaster. From 2014 to the start of the SMO, Ukraine built up its armed forces for one purpose, to retake the Donbas republics. Avdiivka was both a fortress and jumping off point for the offensive. It was knife point driving into the huge Donetsk-Maviika conurbation, a knife point into the heart of the Donbas.
Really the idea that Russia would swap the heart of the Donbas for that bit of land in Kursk.
Zelensky has become ever more delusional. The Ukrainian plan, backed by the Liberal morons in the West was to strangle Crimea economically, but use the army to regain Donetsk city. The loss of Avdiika was then a terrible blow to Ukrainian hopes, or fantasies of regaining all their 2013 empire.
However from a defensive perspective, from the defensive perspective of seeking a compromise peace, where Ukraine would accept that its lost land was gone for good and was just trying to minimise the loss of further land, the loss of Avdiivka was no great defeat, in fact it could even seen as a kind of victory, holding off the Russians for nearly a decade. On one condition, that Ukraine had used those years to fortify a line behind Avdiika. They didn't need to hold that second line behind Avdiika for anywhere near as long as they held Avdiika, but the second line needed to hold for months, long enough to properly prepare a third line of fortifications and long enough to persuade Russia that it would take years, if not decades to really get anywhere.
Similarly from an offensive perspective the loss of Vuhledar is a disaster. Vuhledar was also a knife point, a knife point that allowed Ukraine to strike road, rail and even naval logistic and supply routes into the land-bridge. Of course the capture of Vuheldar will not make the land bridge completely safe, even Moscow is not completely safe from Ukrainian strikes, but every kilometre matters in making the land bridge less vulnerable to logistic isolation. Vuhledar was also a hinge around which the whole Ukrainian southern front was meant to swing, down to the sea to isolate Crimea and then east to retake Mariupol.
But again, similarly to Avdiivka from a defensive perspective, looking forward to a compromise peace, accepting that the lost land is lost, the loss of Vuhledar could even be seen as a victory. On the condition, that the line behind Vuhledar holds. As long as Ukraine still holds Novoukrainka and Bohaivlenka come Christmas I think they can consider the holding of Vuhledar for so long a defensive success.