thank you ! so for sai2 i usually use basic airbrush (opacity ~70%) for lineart + marker/watercolor for coloring

for csp i prefer basic mecanical pencil (lowered opacity again)/gc pen, also this set of brushes is really cool https://assets.clip-studio.com/en-us/detail?id=1683127
and lastly i really love artemus brushes!! they're the best for like a real pencil/chalk/charcoal feel

hope this helps😊💗