I cannot figure out why you cannot get the two screws out inside the porcelain socket... hmmm

However, do not keep twisting the socket or the arm you will be spinning the wire inside and that will cause it to break down.

This has become a project, you will have to take down the entire fixture, go back to the hub in the center take off the bottom cap undo the cluster of wires, then unscrew the arm so yo can work on it independent of the fixture. or take that arm to a repair shop.

Thanks for the advice! Did get the porcelain socket out, but the metal mount it attached to I couldn’t pull out. I wired a new socket to the wires - which a volt pen indicated still had voltage (not telling a whole lot, I know), but it still wasn’t working. Ended up taking it to a lamp repair shop cause I have other projects ongoing, didn’t want to dive too deep into this!