I think the country Bangladesh and Nepal are the only countries banned the bitcoin in their countries but many Asian countries are in the legalization process so we have to wait for the respective governments to announce officially.In my knowledge there are only countries made bitcoin usage illegal in their countries.
You should include China and Vietnam too for restricting their people to bitcoin.
Decentralized, Anonymous, Cant be Taxed, Will affect financial supply.
This are the most common reasons why Bitcoin is banned in some countries. And also don't forget money laundering and funding terrorism.
But I don't know how G20 will affect cryptocurrency value including bitcoin, as it reaches 8k again after some news regarding G20