When comparing numbers one should also compare high-end estimates vs. high-end estimates and conservative numbers vs. conservative numbers.
Half of Gaza are minors, which is quite unusual, and very much not the case in Ukraine.
https://data.unicef.org/how-many/how-many-children-under-18-... (6,609,605 / 37,732,836 )
https://data.unicef.org/how-many/how-many-children-under-18-... (2,415,888 / 5,409,202)
https://www.worldometers.info/world-population/ukraine-popul... "The median age in Ukraine is 41.8 years."
https://www.worldometers.info/world-population/state-of-pale... "The median age in the State of Palestine is 20.1 years."