Would the reward of the rich person who performed many good deeds be greater than that of the less wealthy person who performed similar deeds, but to a lesser extent, and what is the fault of the latter in the reduction of their reward due to their lack of wealth?

The Sunnah indicates that the charity of a poor person in need, even if small, may be better than the charity of a wealthy person, as in the Hadith: "One dirham preceded a hundred thousand dirhams," because the owner of the two dirhams gave half of his wealth, whereas the wealthy person did not give half of his wealth. And "the effort of the one with little" is the best type of charity. Deeds are differentiated in rank before Allah by the differentiation of what is in the hearts, not by their quantity or outward appearance. A person may give a small amount in charity, and Allah blesses it, "just as one of you raises his foal until it becomes like a mountain."