The Russians have worn down the Ukrainian troops in Avdiivka to the point that a rescue mission was organized to extract the defenders before it was too late. Now the rescuers must save themselves along with their besieged brethren.
Avdiivka has become the new Bakhmut where the Russians have ground down their adversaries in a war of attrition. Both sides have probably lost several thousand men and now the numerical superiority of the Russians has won them the city, or what’s left of it.
The next act will be the retreat by the Ukrainian forces down the few roads that can accommodate war vehicles. The Russians have encircled the city and the next day or so will witness whether the retreating army can escape decimation.
This war has been one long series of horrific clashes. With western aid drying up it will be surprising if the Ukrainians manage to continue this war of attrition for much longer.