In Anthem, does Equality 7-2521 completely reject the ideologies, cares and concerns of the society he lives in?
Whether Equality 7-2521 rejects the ideologies, cares and concerns of the society he lives in is irrelevant.
The purpose of his life is not to serve others. His life’s sole objective is to provide joy to himself. He is neither obliged to serve others if that does not give him any joy nor does he have any right to demand that others give up their happiness to provide for him.
Ayn Rand, who came from the USSR, found the philosophy that life is to be lived only for others absolutely absurd. The capitalistic system in the US, which allowed everyone to do what they found joy in and where no one was held responsible for anything that others in society did not have, and provide it for them, was for her the true definition of life.
Equality 7-2521, we see, as the story goes along, in no way harms others. He does nothing that would be labeled as unethical or immoral per se, except by the society that he lives in, where none are to live for themselves but only serve the society.
Then we thought of the meaning of that which lay before us. We can light our tunnel, and the City, and all the Cities of the world with nothing save metal and wires. We can give our brothers a new light, cleaner and brighter than any they have ever known. The power of the sky can be made to do men's bidding. There are no limits to its secrets and its might, and it can be made to grant us anything if we but choose to ask.
When Equality 7-2521 discovers the bulb, he wants to give it for everyone to use as a superior source of light. He approaches them not as a responsibility of his, but as an act that gave him a joy which was only his. And for which others were required to compensate him with what he demanded of them.
No, if you will recall, after rediscovering "Electricity," he brought this "renewed" technology back to the Councils to share his findings with his brothers. He felt it would help lighten their load, and ultimately make life better for all. Despite the fact that he challenged his societies ideologies, he still felt a duty to the greater good, which shows an innate goodness to his character.