To give up being an independent and sovereign country to become a province of a federal EU is indeed national suicide, literally. It's choosing death as a country.
Facing he "Russian threat" obviously does not require this, this is a transparent fallacy and scare tactic to push the EU narrative. Europe faced a worse Russian threat during the Cold War without giving up national sovereignty. Cooperation and military alliances do not require national suicide.
Your replies are very good illustrations of the dellusion and, really post-truth disinformation we are constantly fed in Europe, unfortunately if you do believe what you write. This is becoming very sinister.
The Baltic states used to be in the USSR so I doubt that they would be willing to surrender their sovereignty again. Perhaps that's exactly why the people are never asked if that's what they want!