What is the ruling on the action of a maternal uncle who deceived his nephew in a large project, replacing him with his (the uncle’s) brother? Is the nephew entitled to feel resentment towards his uncle despite the kinship between them?

If your uncle has deceived you, this is legally forbidden and is a characteristic of hypocrites. Patience is obligatory, but it is not necessary for you to forgive one who has wronged you, for forgiveness is appropriate only if it leads to reform. However, if forgiveness leads to corruption, then it is better to uphold justice and not to forgive. The wrongdoing of a relative does not permit severing ties with them, and maintaining ties with a wrongdoing relative brings Allah's aid.