Which of the two is better in Ramadan; seeking knowledge and being keen on attending lessons or abundantly reciting the Quran?

I say that there is no conflict between the two. Combine between the two; specify a time for the Quran, and reading the Quran is seeking knowledge! Also specify a time for some of the lessons that some of the scholars give, there is no conflict Insha'Allah. Organize your time according to what is easier for you and do what is easier.