I was thinking just in terms of murdering children including the specific targetting of children (which the IDF has done both with snippers and by bombing playgrounds).
In absolute terms of civilians, there were a number of worst atrocities, though in terms of percentage of the target population, not so much (possibly none at all but the Nazis, depending on what the the proportion between counted deaths and real deaths amongst the Palestinians is, since those whose corpses were not found and brought to Hospitals - i.e. those still buried in the rubble of the over 70% of Gaza building that were destroyed - were not counted, something which got worse after Israel destroyed almost all Palestinian Hospitals: the 40k deads are likely a significative underestimation and we might never know how significative that is because Israel does not allow independent UN observers to go check it).
What’s really “special” in the genociding done by the Zionists is the number of children being killed, the percentage of the target population killed, the targetting of Hospitals and medical personnel, the targetting of Humanitarian Personnel (worst ever, according to the UN) and the targetting of Journalists.
But, yeah, in absolute numbers of adults killed, things like Darfur and the Rwanda Genocide were worse.