Dallas sits next to 4 phonetic neighbors — Dawson, Davis, and Dalton are the closest matches by sound. Most share Dallas's Scottish cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"meadow dwelling, water meadow"
"divine messenger"
"consecrated; worthy of reverence"
"God has given"
"young horse tender"
"red king, famous ruler"
"son of David"
"healer, to heal"
"he who descends, descent"
"little king; descendant of the king"
"people's king"
"winding valley"
"title of honor, great one"
"counsel's guardian"
"home ruler"
"crooked nose"
"befitting a king"
"to carry, to endure"
"God is gracious (via Jack, from John)"
"rye-field dweller"
"narrow road, path"
Similar sound: These names share phonetic patterns with Dallas — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Scottish Gaelic origins, giving them the same cultural heritage as Dallas.
Rhythm: Dallas is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.