The three things I think could actually be feasibly used to take out the tunnel networks (aside from taking the L and just sending most of your army down there to get murdered but eventually take them all out) are, in order of effectiveness, a) nuclear weapons; b) thermobaric bombs; and c) bunker busters. I just can't imagine how Hamas could possibly have seen flooding being used against their smuggling tunnels by Egypt a few years back, and not gone "Hm, if this isn't a problem we've already sorted out, then we really should get on that if we're actually going to try and do this major attack to draw Israel in to cripple and humiliate their army and lead to a Palestinian state one way or another." Like, it's one of those very obvious and basic issues that you should expect your enemy to try and do - so failing to mitigate it in an operation that has so far been marked by its very good planning and foresight and preparation would be very odd. If Israel had developed some superweapon in the last year, then obviously Hamas might not have the time or resources to counter it, but flooding tunnels to kill the people in there was something tried against the Viet Cong half a fucking century ago, and honestly has probably been a thing for centuries before that in more limited places.

I'm a little confused why the bunker busters haven't seemed to have done that much - of course, it could be total chaos down there with collapsed passages and we just don't know - but it's probably some combination of sufficient depth and Israel just not knowing where to drop them.

Thermobaric bombs seem pretty promising, so the fact that they haven't tried them yet is interesting. I don't believe the faux concern about civilians for a second, they would totally drop a thousand of them on Gaza while doing the Fortnite default dance if they thought it would work and that the rest of the Resistance, most notably Hezbollah, wouldn't start blasting and destroying the country. I'm unsure what's going on with them not trying them, at least not that we know of. Russia has used them in Ukraine, but if they were really THAT effective against soldiers in fortified positions, then we wouldn't still be talking about fucking Avdiivka. I don't know how many civilians still live there that could also be hit by them, but approaching 2 years of this war, it can't be THAT many, right? And what about in trench systems that are away from notable settlements? If thermobaric bombs are that great, why aren't they used there? I don't really know, a military guy would have to tell me.

Nukes and the problems they would generate go without saying of course. I'm unsure how much damage a nuclear blast above ground would cause to people in relatively unreinforced tunnels or bunkers (there's certainly stone or concrete there from the images, but not layers of steel or lead or whatever). Dropped in the tunnels, well, I don't see how you'd survive that even from quite far away, so long as you're in the same tunnel network. Though idk, maybe you'd have to get the nuke pretty deep in there to ensure the energy stays mostly in the tunnel, and that might be an issue all by itself. But this seems like a thing where if we actually have to seriously discuss this, we should probably be preparing for the end of the world and not be on Hexbear.