Sung sits next to 5 phonetic neighbors — Song, Sun, and Soong are the closest matches by sound. Most share Sung's Chinese cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"to succeed, accomplished"
"of Thor, thunder"
"God is my oath"
"God adds"
"follower of Dionysus"
"follower of Christ"
"wise counsel, gentle (ewe)"
"eagle"
"shining renown"
"prince, hill settlement"
"faith"
"gray fort or enclosure"
"gift of God"
"fertile plain"
"Gaelic form of Jane/Jean"
"smiled, one who smiles"
Similar sound: These names share phonetic patterns with Sung — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Korean/Chinese 成 origins, giving them the same cultural heritage as Sung.
Rhythm: Sung is a 1-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.