we cant repair severed fiber optics cables and censorship blocks can be bypassed with a proxy tho

Hacking into the mainframe to turn the internets back on, bro. No worries.

There are alternatives like mesh networks and radio, but recently in Afghanistan they cut off the internet… Literally. They severed the lines and made the entire country dark.

No private citizen has enough money to fund their own DNS and fiber backbone like a few people in Europe or USA can. The countries you mentioned have the State control all the DNS servers and fiber channels that ingress/egress the country because they control all the money, so they can simply disconnect power supply to the facilities and put the maintenance employees on furlough to completely shut off the network.

Next question.

If you have control of the national uplinks to the rest of the world, it’s quite the simple affair to turn off traffic for ISPs. If you are a telecom provider and you are visited by military with authority to shoot you on the spot, you are quite inclined to obey and shut down the network as it will happen regardless you are alive or not.

Whatever wired local city networks may still function or not, depending on circumstances and the phase of the moon. Likely they will not be able to communicate with anybody else though.

Then there is nothing much to do for any opposition but to use covert satellite communications and those are much too important and slow and expensive for sharing with memes and porn.