I have 2 nationalities. I view this as something I can take advantage of under the current system, and I feel no loyalty to either of those countries, and I don't live in either of them. When people ask me where I come from, I'd rather say my state or the local city of my area as opposed to the country as a whole. I also understand that where I come from has an impact on my socialisation, and that I have to a certain extent absorbed like cultural norms/values from those places, though to be fair this can also change quite a lot within a certain country.
I would say that I'm also pretty good at behaving in the manner expected of me when I'm in either of those countries(as in following the rules of politeness, basic understanding of the laws, and what not). I feel at home(comfortable, on familiar ground) when I go to either of those places, but I feel like I get treated like a foreigner in both of them to a certain extent.

In the sense that I am legally a citizen somewhere, sure. In the sense that it is part of my identity, no.

I do in the sense of having a particular experience attributed to my locality and descendance. Combine those two and you get locaility (US) and descendance (African: former slave).

Growing up, I would have considered myself a person from my area of my state more than from the US as a whole, though. That was something that used to give me pride when I was young because of the particular experiences my community made it through.

I don't view nationality as much of a real issue in isolation so much as what it means in relation to other things. I view religion in the same way.

Legally, yes. And I'm for sure culturally of this land, but it wasn't a nation until very recently so I couldn't care less about its political identity.

How do you notice nationality impacting the way you behave in some contexts? Curious, dont feel obligated to get uncomfortably specific if you dont want to tho. Not tryna dox anybody lol this is a risky click

All being "American" means to me is that my mother gave birth to me within the imaginary lines that are designated as the United States. I have no attachment to the culture; own no land; and I'm descended from slaves, immigrants, and whatever Puerto Ricans are to the US government.

I'll stop here before I start ranting about how nonsensical the concept of nationality is.

The phenomenon which I'm now attempting to describe isn't legal nationality. I have lived in both countries, my father was diaspora and I spent most of my adult life in his home country, so I have spent lots of time in both countries. I guess people in both countries do things differently, especially in the public life. How people expect you to act and speak changes depending on where you are.
So I have that understanding of both places, and act like it when appropriate. This is about social/cultural knowledge rather than legal nationality, and I said before this can also vary quite a lot within national boundaries as well as without. Also any foreigner coming into a new country can learn this as well and so become fully acculturated while still having the same knowledge of their home country. And also this would be the case regardless of the existence of the state. I would like to add that I am currently the foreigner doing this exact thing in the new country, if I stay here long enough, and make the effort, then I can gain this social/cultural knowledge and as a result the 'nationality'. Hopefully that was helpful.

Kind of... I grew up and live in a foreign country, a country that used to colonize the country that I was born in, so I have natural(?) animosity towards it.