Is family planning by having two children better than having five children or more, taking into account that every child has their sustenance?

What your friend said is true, in accordance with the Almighty's saying: ﴿And there is no creature on earth but that upon Allah is its provision. And He knows its place of settlement and where it is deposited. All is in a clear register.﴾ [Hud: 6], and the saying of the Prophet, peace and blessings be upon him: "Indeed, Allah commands an angel, when the soul is breathed into the fetus, to write its provision, its lifespan, and whether it will be wretched or happy." Therefore, it is obligatory to believe that provisions are in Allah's hands, predetermined and written, and that having many children or few does not increase or decrease one's provision. Regulating births out of fear of poverty is a sign of ill-conjecture about Allah and weak faith.