Countries like El salvador accumulating more BTC isn’t bad in my opinion, this will definitely result in price increase and that’s good one after all.
It won’t be bad for them to accumulate more bitcoin but the thing is they are even among the lowest Bitcoin holders among countries which hold Bitcoin even as they made it a legal tender, their resources won’t allow them to have much more compare to what other countries have acquired through seizure, price increase is not only attached to countries having more bitcoin, as that have more negative effect than positive one.
First, it will not be good for the government to have the most of Bitcoin because they might find a way to control it despite being decentralised and that can't be good. It may be a good thing initially to help the price pump, but with time, it will not be. Again, you can't blame the government for not buying Bitcoin, Bitcoin itself is risky in terms of volatility and they have to be cautious of what they can't control. And this doesn't mean they do not invest, governments invest in various ways and forms.