Are you asking why birth rates increase when material conditions worsen?
Pre-war Gaza had a number of salient features that set it apart from the rest of the occupied Palestinian territories. Among them were: a high population density, with an estimated 2.3 million people squeezed into 365 square kilometers (141 square miles); a large number of UN-registered refugees, amounting to 70% of Gazans, the majority of whom lived in eight overcrowded and squalid UN-serviced refugee camps; a population that was increasing annually by 2.8% — among the highest growth rates in the world, with nearly 50% under the age of 18; and a fast-growing labor force, with new entrants to the job market joining long unemployment lines in a small and virtually broken economy.
High rates of joblessness, especially among youth (60%) and women (64%), widespread poverty (64%), and severe food insecurity (41%) produced extremely dire living conditions, rendering 80% of Gaza residents dependent on humanitarian aid for survival. Dilapidated infrastructure, environmental degradation, institutional decay, and chronic shortages in electricity and potable water added further strains. The severity of conditions in Gaza twice led the UN, in 2012 and again in 2015, to warn that if nothing was done to reverse course, the whole place would become unlivable by the year 2020.
These things aren’t linear, you could try to piece together a projection from the reports on famine. But they deal more with how to prevent and reverse famine, not death projections
https://www.refugeesinternational.org/reports-briefs/untangling-the-reality-of-famine-in-gaza/