As for the 500k figure, I'm not interested in disputing it since it's just as irrelevant as your 6.6% figure, for reasons I've already mentioned. But since you insist, I'll list them out again:
1. That figure is listing total exits, not distinct exiting individuals. Since most of those exits were made by workers and traders (who might cross very frequently, maybe daily), there is good reason to believe that the number of distinct exiting individuals is vastly lower. For example, if everyone crossing was a daily trader, the true number of exiting individuals would be smaller by a factor of 365. Of course, not everyone making the crossing is a worker or trader, only most of them, and we don't know how often they cross.
2. That figure does not distinguish exits by Palestinians, Israelis, or other citizens, so it has no bearing on whether Palestinians are trapped in Gaza or not. Many Israeli workers also cross into and out of Gaza constantly.
3. This figure is from before October 7, and movement is more restricted now. But, since you are focusing on the use of the term "open-air prison" before the massacre, I won't count that against you.
By the way, I certainly don't insist on calling Gaza an "open-air prison", that's far too imprecise for me. I simply object to the way that you misinterpret facts to support your argument.
There isn't any report that actually counts Gaza's population, the UN provided an "estimate" with no methodology, births are not mentioned, and it's built on figures including number of people who exited Gaza (irrelevant to the claimed decrease due to violent deaths). That's not serious.
There's no coherent notion of genocide that fails to reduce the population significantly. Yes, you can argue (and people have) that the legal definition, by using the "part of" wording, can conceivably apply to virtually any number of deaths, but again, that's not serious.
I would also like to note that you found a study looking at birth/death rates, but after realizing it suggested a shrinking population, decided to combine information from that study with information from a separate dataset so that the population could be argued to be growing.
And none of this actually takes nonviolent deaths into account, however small you believe that number may be.
This... is not good science.