The -n ending crosses origins: Hebrew (Ethan, Nathan, Benjamin), Celtic (Ronan, Declan, Finn), Anglo-Saxon (Owen, Mason, Jackson), Greek (Sebastian, Jason). It is one of the most flexible endings in English naming.
Why -n endings feel grounded
A final consonant closes the name with authority. That is part of why these names read as steady and unshowy. They also pair well with almost any middle name, since the clean ending leaves room for a softer follow-on.