Dylann sits next to 3 phonetic neighbors — Dylan, Dillon, and Dillan are the closest matches by sound. Most share Dylann's Welsh cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"son of the wave, born of the sea"
"son of Walter, ruler of the army"
"claw, swift predator (via Talon)"
"from Dyce, Aberdeenshire"
"little king, kingly"
"who is like God"
"from the east, east settlement"
"modern invented name, combination of Tae and -vion"
"land, territory"
"hope, aspiration"
"red-haired king"
"bright, splendid"
"unit of luminous flux (scientific)"
"God is gracious (via Shawn)"
"aunt"
"pure"
"speech, language, of God"
"invented modern name"
"resembling the bright one"
"something deserved, virtue"
Similar sound: These names share phonetic patterns with Dylann — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Welsh mythology origins, giving them the same cultural heritage as Dylann.
Rhythm: Dylann is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.