The above is not in contradiction of what I've been saying, in all honesty. It appears you've posted it believing it is which shows you don't understand what proportionality means under Law Of Armed Conflict.
LOAC doesn't define proportionality in terms of numbers of dead on one side versus another. Rather, it defines it in terms of lives lost in comparison with a military objective.
Using your quote:
"The principle of proportionality prohibits attacks against military objectives which are “expected to cause incidental loss of civilian life, injury to civilians, damage to civilian objects, or a combination thereof, which would be excessive in relation to the concrete and direct military advantage anticipated”.
The second quote you used makes the same point:
"In other words, the principle of proportionality seeks to limit damage caused by military operations by requiring that the effects of the means and methods of warfare used must not be disproportionate to the military advantage sought.”
The link to the screenshot I provided in my last post to you explains all this, including referencing the ICRC website you have quoted from:
https://www.justsecurity.org/89489/expert-guidance-law-of-armed-conflict-in-the-israel-hamas-war/
Screenshot attached again.
So, in LOAC proportionality is based on the military advantage reasonably sought, anticipated and/or expected.
Not numbers of dead for the simple reason there can be zero guarantees by ANY State that civilian deaths can be prevented in conflicts.