What are the most beneficial outlets for Muslims for funds bequeathed for charitable works and philanthropy, and is it permissible to spend them on high-cost da'wah projects and lavish buildings?

The intended meaning of "acts of piety and benevolence" in a will refers to deeds that benefit Muslims, and their importance varies depending on the time and place. The executor should determine the most beneficial, such as: building mosques or schools, spreading religious knowledge, helping youth get married, or providing medical services. The executor must fear Allah, and it is permissible to spend money on da'wah (preaching) matters if they are important for spreading Islam, provided that funds are not wasted and expenses are reasonable.