If the Bank is completely against bitcoin then we cannot convert bitcoin to fiat currency through the Bank's services. I think the Bank is not really opposing it but rather limiting it because they are worried that bitcoin will become a competitor and it is not the Bank that is opposing bitcoin but rather the government with its laws. I don't know how it is in your country but we have banking services to convert bitcoin to fiat and even taxes are regulated in such a way.

Every system that has been built will always be maintained by the government, in this case the bank as an institution providing money will think about how this system does not collapse. Banks are controlled by the government, while Bitcoin does not have anyone's control, so the government is worried about the development of adoption that will occur.