Warning: Speaking for family one step removed to be clear, so some subjectivity in opinion and somewhat anecdotal.
My aunt’s family has dual Israeli / US citizenship. My aunt, her husband, and my 3 cousins moved to Israel around the time I was born, and my cousins were all minor children at the time.
All three of my cousins came back to the US for college, and two of the three have lived in the US nearly exclusively since, though they still visit often. The youngest returned and lived almost exclusively in Israel after college.
So, for the two eldest, figure 8-12 years of their formative years in Israel, followed by nearly 30 of being predominantly US residents.
BUT - when it comes to US politics, they vote almost exclusively based on how the candidate for whatever office stands on Israel. Rather than what may or may not be best for US citizens.
I suspect that for them, plus likely for any number of actual dual citizenship posters, that where you were, when/how old you were at the time, and the circumstances for gaining your dual citizenship is going to determine where your heart is.
Speaking for myself only, on a related subject, I spent most of my formative years growing up in Southern New Mexico, despite being born and living in MASS until I was nearly 6, and living in Colorado on and off since College (exclusively for the last 30 years). And yet, at some level, I consider myself a New Mexican in food and attitudes.
It was where I was, and what pervaded me when I became, well, ME. So it informs my deepest assumptions. I suspect the same for my dual-citizenship cousins, no matter how many decades of acculturation.
NOTE: THIS IS NOT SOME STATEMENT THAT AMERICAN JEWS HAVE DIVIDED LOYALTIES. Sorry for the all caps, but I see that BS in plenty of places, although not much here, granted. It’s that anyone who has spent a great deal of time, much less growing up in a nation may have a great fondness, memories, and sympathy for that nation even if they no longer reside there, especially so if they left under pleasant (and even for some who left with far less than pleasant) circumstances. Moreso if they have friends and family who remain.
Sorry, for the all caps, but wanted to be extra clear on that point.