Between the zikr of La ilaha Illa Allah that is synchronized with heart beat and body pulse and Allah Allah Allah continuously, which one of the two is preferable.
Thanks and God bless

Both are good but as quran said
الَّذِينَ آمَنُوا وَتَطْمَئِنُّ قُلُوبُهُم بِذِكْرِ اللَّهِ أَلَا بِذِكْرِ اللَّهِ تَطْمَئِنُّ الْقُلُوبُ

Those who believe and whose hearts are set at rest by the remembrance of Allah; now surely by Allah's remembrance are the hearts set at rest.
Sura Raad ayah 28.