Some nations recognize the right of their citizens to acquire another citizenship.
Some countries do not. Here are some considerations and facts...
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Suppose you are European and become a Brazilian citizen.
You probably do not need to declare this to your country of citizenship.
So you keep that passport. You are a dual citizen...
But in Brazil, you are Brazilian. In Europe (x-country) you are a European.
When you travel, you can be a Brazilian or a European.
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In Brazil, you are NOT a dual citizen. You became Brazilian, so you are Brazilian.
You cannot wave your European passport in Brazil.
You cannot say "this does not apply to me, I am European...!".
If you enter Brazil, with a European passport, your passport is stamped for ENTRY.
There is a limit of time you can be in Brazil... say 30 or 90 days for Europeans.
If 6 months later, you are in Brazil, and use your European passport, you have exceeded that limit.
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Same thing in Europe, if you enter using your Brazilian passport.
If you wish to use your Brazilian citizenship, remember you are limited to stay 30 or 90 days...
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I had 3 passports...
One from Belgium (born there), a USA passport (lived there 25 years) and now an Argentina passport.
In Argentina, I am NOT a Belgian or USA citizen. I am Argentino.
When I visit back home in Brussels, I use my Belgian passport.
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Is there a country where "even" days you are one nationality, and "odd" days the other...?
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Happy contrails