Ukraine has a proper army with proper weapons and strong foreign support; Gaza only has a bunch of militias with outdated arms and makeshift rockets. Obviously, fighting Gaza is easier than fighting Ukraine.

> that seems plenty strong enough to level a modern city in a few days or weeks

How would they do this?

The don’t control the sky or the ground. It’s down to ballistic missiles and drones. Many of these can be shot down.

Scale doesn't really matter with an air force. The IAF is much, much stronger and more competent than the Russian Air Force. Plus, the Israelis are bombing defenseless cities (in Lebanon), and getting a lot of help from the US (in Iran).

Israel can fly aircraft over their adversaries at will. Russia can't.

To be frank, you seem to have a cartoon's idea of war.

US is the only country that maybe has a capability to carpet bomb someone to rubble. Russia has always preferred to do it with Artillery anyway, which they have done to many many Ukrainian cities.

A prolonged strategic bombing campaign that can "Wipe a city off a map" takes weeks, hundreds of bombers, and tens of thousands of tons of explosive, and either air supremacy to protect your bombers (not sufficient against a target with SAMs) or the ability to build hundreds of those bombers fresh.

Literally nobody can do that anymore. America can maybe do that once or twice. Only 60ish B52s even remain.