This trains independence. Keep one finger planted on a string while the others move.
Mauro Giuliani (1781–1829) wrote a treatise called 120 Right-Hand Arpeggios . While 120 is overwhelming for beginners, the first 12 are essential. A good PDF will show these patterns using pima notation. This trains independence
The phrase " Classical Guitar Technique: Essential Exercises, Scales, and Arpeggios This trains independence