in this case, i would aplly solder mask on every ground contact and leave clk trace and via exposed. Then aplly some flux on it and low temperature melt solder paste (try to create a bulb to connect both). if it doesn´t work, cut a small piece of copper wire and use it has a bridge. Dont use a solder iron, it´s easier with a heat gun. Dont forget to put some kapton tape to prevent some solder ball to get under the CPU.Thank, do you recommend I do the wire or the blob for the sake of testing? I am waiting on my solder mask and microscope before I do anything