I didn't think you were a Christian, tbh. There's a bit of a conflict between liking Jesus, for His moral code & disliking Christianity, though. Obviously, since you don't believe in Christianity, you don't believe it's true but you'd, presumably, agree that those who do believe are entitled to do so?
As long as they're not preaching it at you, that is but I wasn't & you're coming at me with 'it's a lie' & all that! However, let's suppose, for a moment, this other species did engineer us with their DNA, that'd be aliens, not god. There isn't, yet, the evidence to support that belief enough to use it as an explanation of life here, for a start. Then, even allowing that, for now, it only transfers the question to their planet. How and why did life start there, if we need to bring them in to explain life here? This could be a good discussion!