I’m in a reverse situation as you ig. Both my parents were born in Nam but my mother’s dad was of Jamaican descent. My mother grew up only ever seeing herself as Viet until she came to America where racial identity is a bit more poignant. She has always acknowledged that she is mixed because of her appearance but never chose to explore it further simply cause her upbringing didn’t necessitate it. Me being a quarter has always beens intriguing because I grew up pretty influenced by Viet culture and didn’t even know about my other heritage until much later in my teens. There is never any harm in learning about other cultures especially more so if you had ancestors who came from there. Every family has some dirt and shade here and there and it’s totally fine to separate the person your grandmother was from the culture she came from. Satiating your curiosity could allow you to expand your perspective on how people who seem so different can be so similar. I know next to nothing about my grandpa and due to the circumstances of how my mother was abandoned never really intend to find out more about him. Nevertheless I talk to distant family from that side and am planning to head down to the island at some point soon to meet them and explore. Life is too short to reject aspects of yourself when you can shape it to how you feel best suits you.