i wasn't the only critic of your idea
I've seen this happen in my own mind as my internal monologue switched languages after watching a lot of english TV and Youtube.
maybe you should read instead of "watching TV and Youtube"
The problem with nationalism, why it is nationalism, is the idea that only a certain group of people are deserving or valid in a culture.
Nationalism "further aims to build, and maintain, a single national identity, based on a combination of shared social characteristics such as culture, ethnicity, homeland, language, politics (or government), religion, traditions, or belief in a shared singular history, and to promote national unity or solidarity."
France for example is a multicultural nation. One can "be French" without belonging to a certain culture. There are some shared values but nation, being an artifice, is redefined constantly. Still, you won't be seeing anarchists with tricolor flags there. They may carry the black flag (or the red/black) but it would be absurd to draw circled A on a national flag.
Maybe you're not an anarchist after all. Maybe being Estonian will overpower your libertarian flame in time.
maybe you will end up being a flag merchant 🤷