Change in government - it's simply means when another government enter there's will be reduction or addition of some policies.
Political instability - when political system in the country is not stable, everything will get down.
I consider government as a major factor that is affecting government, government propaganda towards cryptocubutrrency is primary challenges of bitcoin today, because of government so many countries are adopting the policy of banning cryptocurrency, so another secondary cryptocurrency challenges is Elon musk procrastination, castigations, circulation of fake information towards the development of cryptocurrency especially bitcoin across the world, all these are bringing setback of crypto sphere into different nation.