Darwin sits next to 3 phonetic neighbors — Marvin, Derwin, and Garwin are the closest matches by sound. Most share Darwin's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"beloved companion"
"king's meadow, king's clearing"
"resolute protector's son"
"soldier"
"God is salvation"
"queen's settlement"
"Lord (via Kyrie element)"
"bringer of treasure (gift-bearer)"
"dweller by wild land"
"wild goat (ibex)"
"ruler, sovereign"
"brave in power"
"protector of mankind"
"son of David"
"from the Denzell estate"
"to follow a course, leave a mark"
"fire (Irish equivalent Aodh)"
"son of Cole"
"God will add, God will increase"
"new house"
"settlement at the inhospitable place"
Similar sound: These names share phonetic patterns with Darwin — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old English origins, giving them the same cultural heritage as Darwin.
Rhythm: Darwin is a 2-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.