Agreed, writers can always come up with something, but I doubt even all of Ego's energies compares to the power of deleting or returning half of all living things in the universe.
You say that as if "all of Ego's energies" is anything other than a narrative tool. Comics continuity is not a simulation such that we can say with authority, "Well, the writers couldn't do that because..."
Peter Quill, with a heritage of Ego's energy (probably much less than half, admittedly) could barely hold onto the Power Stone. Ego, powerful as he was, was finite; the Infinity Stones are (like it says on the tin) infinite.![]()
No Prize - sure, the energy of the Snap is bigger, but it is spread over the whole universe. Ego's energy is lesser, but only spread across one galaxy. They could have similar energy densities, such that whatever Earth-local thing is happening could be started by either.
See how easy that was? It just doesn't pay to make logical arguments against narrative props. Such narration should be vetted by thematic appropriateness, not our presumptions of measurements of fictional energies.