Governments will have no power if people simply refuse to use their money.

Hyperinflation or attempts to introduce CBDCs will just cause the population to rapidly shift to the already well established and far more efficient cryptocurrency financial system. Just download an app. There will be no ramps for the government to control.
Those people and merchants who move to sound money will prosper and those that don't will suffer and fail and then follow the crowd over to the new crypto based financial system.

Governments can't actually force people to do anything if the people reject their money. Firstly there are never enough police and soldiers to force the people to act against their interests and secondly there will be very few police and soldiers willing to work for a government that can only pay them in something no one else wants.