Hi farhan, I am also Bangladeshi. Bitcoin and cryptocurrency is still illegal in Bangladesh. Recently Bangladesh Bank has banned again cryptocurrency by showing it as a means of helping in terroristic activities and Money laundering. So you can work here and cryptocurrency trade with your own risk.
Understand and study first of all the legislation in your country. First of all, you need to know the reason why your country banned the bitcoin in the first place, and do not do it, in my opinion, I do not think that any government or anyone can prevent people from using bitcoin