Is a client's dealing with a bank to finance the purchase of an apartment via a check or bank transfer directly to the property owner considered usury, especially given the client's inability to delay payment of the due installment?

An interest-based loan (riba) is forbidden, and it is not permissible to engage in it except out of necessity. Necessity is defined as a state of extreme danger or hardship that results in harm to oneself or one's property. This does not apply to purchasing a house or a car. One can seek out Sharia-compliant alternatives, such as Tawarruq with Islamic banks. And whoever fears Allah, He will make his matter easy and provide for him from sources he never anticipated.