Let us put it this way, every Central Bank has its own protocols and so crypto regulations may vary from country to country. Thus, we don't know exactly their regulations when it comes to crypto. But right now, we are seeing that some Banks/Central Banks owned by the government are publicly stating their stance towards btc or crypto in general. And most of them are positive on this market.
The country by country accepting is the important part. If we get more and more nations accept it, then we are going to see big ones accept it as well. When it comes to big ones like USA, or Russia or China or UK, then we already achieved what we want because if those accept it, then it's okay.
I understand that smaller nations will be following those big ones so that the gap doesn't grow even further. It is not that easy, and it takes time, but it can happen and not that bad. I fear that we are not going to see this changing anytime soon, so we need those big guns to show up and accept it as reserves. Most of them are already building something like that, which means that it is going to be pretty great for all of us.