Is it considered a usurious loan if I take my principal plus an additional lump sum (estimated profits) in exchange for waiving my share in a residential building, knowing that I was a partner with a share in the construction but did not receive my portion from the sale of the completed apartments due to their delay in other projects?

Abu Dawud and Al-Bayhaqi narrated that Allah the Almighty says: "I am the third of two partners as long as one of them does not betray his companion." Preventing a partner from his share or procrastinating in paying him his right is a betrayal and an injustice. Allah the Almighty says: "And indeed, many associates oppress one another, except for those who believe and do righteous deeds—and few are they." A valid partnership requires the partner to have a common right in the company's assets. Accordingly, you cannot be prevented from your right in the building or be procrastinated in receiving it, nor can you be compelled to sell your share. You are entitled to a common percentage of the apartment that was sold, commensurate with your share in it and its profit. As for the rest of the money, if it is cash or owed by the partners, it is not permissible to sell your share for less or more, and it is permissible to take it in cash or in exchange for goods. If the money was used to buy building materials or goods, there is no harm in you giving up your share for more money.