The UN Convention on Genocide defines it like this:

https://www.un.org/en/genocideprevention/genocide.shtml

"a) Killing members of the group;

b) Causing serious bodily or mental harm to members of the group;

c) Deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part;

d) Imposing measures intended to prevent births within the group;

e) Forcibly transferring children of the group to another group."

So, point for point, the only one Israel hasn’t done in Gaza is “e”. But to be clear, you don’t have to hit all 5 to be a genocide, just one is enough. Russia is hitting all 5 in Ukraine.