琴棋书画 is translated as the "The Four Accomplishments" which a person is considered educated in ancient China. 迷 = intoxicated, drunk, confused etc but with negative connotation. It means that one is so into practising writing that one forgets everything else like being a drunkard and forgetting everything else. In other words, being obsessive or addictive. Nevertheless, a negative implication. 于 = into, a Classical Chinese term.

况迷is incorrect maybe 痴迷 or 醉心 is more better