The Greek word "through" in Hebrews 1:2 is "dia". Does this Greek word suggest an eternal Son or not? Or does it mean "because of" or "for the reason of" the Son as Socinians and Modalists usually argue?

Dia comes with the accusative case and the genitive case. What is the case that accompanies dia in Hebrews 1:2?

[In this video, I meant to say dia 'with' the genitive case rather than 'in' the genitive case. Apologies :-)]