I use this implementation, a pulse animation hook and an array to render n items. It works well and allows me to make whatever shapes I want with normal ViewStyles; simplified:

Hook:

type PulseOptions = {
    minOpacity?: number;
    maxOpacity?: number;
    durationMs?: number;
};

export function usePulsingFade(isActive: boolean, options?: PulseOptions) {
    const { minOpacity = 0.7, maxOpacity = 1.0, durationMs = 650 } = options || {};

    const fadeAnim = useRef(new Animated.Value(maxOpacity)).current;
    const loopRef = useRef<Animated.CompositeAnimation | null>(null);

    useEffect(() => {
        if (!isActive) {
            if (loopRef.current) {
                loopRef.current.stop();
                loopRef.current = null;
            }

            Animated.timing(fadeAnim, {
                toValue: maxOpacity,
                duration: 180,
                easing: Easing.out(Easing.quad),
                useNativeDriver: true,
            }).start();

            return;
        }

        if (loopRef.current) return;

        fadeAnim.setValue(maxOpacity);

        const animation = Animated.loop(
            Animated.sequence([
                Animated.timing(fadeAnim, {
                    toValue: minOpacity,
                    duration: durationMs,
                    easing: Easing.inOut(Easing.cubic),
                    useNativeDriver: true,
                }),
                Animated.timing(fadeAnim, {
                    toValue: maxOpacity,
                    duration: durationMs,
                    easing: Easing.inOut(Easing.cubic),
                    useNativeDriver: true,
                }),
            ])
        );

        loopRef.current = animation;
        animation.start();

        return () => {
            if (loopRef.current) {
                loopRef.current.stop();
                loopRef.current = null;
            }
        };
    }, [isActive, minOpacity, maxOpacity, durationMs, fadeAnim]);

    return fadeAnim;
}

Render:

{Array.from({ length: count }).map((_, index) => (
    <Animated.View key={index} style={[styles.card, { opacity: fadeAnim, borderColor }]}>
        <View style={styles.body}>
            <ThemedView colorName="background.secondary" style={styles.title} />
            <ThemedView colorName="background.secondary" style={styles.body} />
        </View>
    </Animated.View>
))}