السلام عليكم ورحمة الله وبركاته أحسن الله إليكم، How can one attain happiness, a life of piety and ilm , striving to be from the awliyaa of Allah and having this feeling that one wouldn't trade even for the whole dunya?

Allah described His awliya' in Surah Yunus, ayat 62 to 63, as those who believed and used to have taqwa, so it is iman and taqwa, not a rank handed to a few. Imam Ibn Baz said the most important matter in seeking knowledge is ikhlas, that you seek it for Allah and not for any other purpose, and that when the worshipper's knowledge of Allah grows strong that is a cause for the completion of his taqwa.