Bereaksi margin dasar flatlist asli
<FlatList
data={...}
renderItem={...}
horizontal={true}
contentInset={{ right: 20, top: 0, left: 0, bottom: 0 }}
/>
FinnMal
<FlatList
data={...}
renderItem={...}
horizontal={true}
contentInset={{ right: 20, top: 0, left: 0, bottom: 0 }}
/>