There is an extensive scholarly literature on the effectiveness of sanctions, including blockades. You don't know it, but I do. The unambiguous result of that research is the finding that sanctions are usually counterproductive. They don't defeat the regime they are imposed against; they strengthen it, because now the rulers control all commerce. This has been true in Iran, North Korea, Syria, Russia of course, etc.
If Israel had not blockaded, if Israel had let Gaza develop, there would likely not have been a 10/7. Hamas would not have had a stranglehold on the entire region, as other centers of financial power would emerge. The reason that the imported supplies were used for weapons is that they couldn't be used for anything else. Literally, if you're smuggling in pipes, you can't use the pipes to build, oh I don't know, a factory because then people will ask where'd you get the pipes. The only place the pipes can be used is in the tunnels to build weapons. Absent the blockade, that would not have been true.
Hamas are bastards but they were never strong until the blockade. Israel made them more powerful than they had ever been.