I don't think they miscalculated. Almost everything in this benefit them in almost every possible ways. The horrors of Gaza makes them almost look nice to the eyes of some (they never have been more popular in Palestine and in the world), and makes sure they will have no shortage of terrorists in the many years to come, among the innocent victims and their brothers and sons/orphans. I don't imagine they care or didn't anticipate for those killing of innocent people.

Gaza suffering is the best thing for Hamas. Israel is doing the best possible thing for Hamas and that's why Israel should stop. Because worse than unjustified, their actions are stupid, unless you are a politician saving face.

Pray tell, imagine yourself as a 10 year old Palestinian kid who lost half of his family, his house and several friends to Israeli military action. What are the odds that you are willing to die in order to harm Israel in any way, shape or form?

Again, this is the best scenario for Hamas. Their leaders are literally not even in Palestine, Israel could decimate the population thrice and chances are that the amount of terrorists would increase.

I think it's pretty clear Hamas's main objective was to derail the rapprochement between Israel and Saudi Arabia. They achieved that. It's also clear they don't care what the cost is to Gazans.