Hamas casualties make up only a portion of palestinian casualties; palestinian casualties make up only a portion of excess deaths; excess deaths make up only a portion of total deaths.
It’s not clear that Hamas limits their counts to excess deaths. Even if they intended to, a lot of it is based on a web form, with not much validation besides basic checks that the person exists etc.
As with pretty much any conflict, there's a ton of uncertainly, and people shouldn't be recklessly speculating based on things like WhatsApp chats. Responsible casualty estimates would look more like Ukraine, where for example Zelenskyy said "tens of thousands" (one significant digit) were killed in Mariupol.
>the casualty count that Hamas claims
The Gaza Health Ministry's count is widely regarded as an underestimate, but mostly by people who don't refer to it with a dogwhistling caveat.
50,000 births by july of 2024 (starting with october 7th 2023) [2]
you can sum and extrapolate the numbers. you can probably find more numbers about births
[1] https://www.savethechildren.net/news/about-130-children-born...
[2] https://www.savethechildren.net/news/women-self-inducing-lab...