Lal said: Micca ditthi can be removed only by learning true dhamma AND by actually practicing (book knowledge is not enough).
Certainly true. I quote from MN.43, a conversation between Venerable Koṭṭhita and Venerable Sariputta…
https://suttacentral.net/mn43/en/sujato
“But how many conditions are there, your reverence, for bringing right understanding into existence?” “There are two conditions, your reverence, for bringing right understanding into existence: the utterance of another (person) and wise attention. Your reverence, these are the two conditions for bringing right understanding into existence.”