If there are already funds with names starting with the same first word, but ending in"fund" and "capital", and my fund name has the same first word but uses "Ventures" and the exact word combination is not registered as an entity in Delaware or anywhere and the domain is available, is my fund name still too similar to use?
Yes it is and you should change you name. Even if you could technically win a legal dispute, the effort and the cost would not justify it.