If something like that were to happen, bitcoin will no longer be valuable. A network that cannot safeguard the users’ value will no longer be trusted by users.

The network can try to fork, but it will be hard to decide which point to begin the fork for the reasons you outlined very well. Also, reversing transactions is a precedent that we do not want to set, no matter the reason; because once that precedent is set, someone will always find some other reason to do the same. Then it becomes a slippery slope to become a shitcoin like Eth, where you can just roll back the chain for whatever reason. Even if the network manages to fork and stay alive, it will take some time for people to gain confidence in the network again.