Of course there is merit to the idea if we're talking about ideas promulgated by individual actors such as Stephen Miller or the underlying rationale for specific policies such as preferential treatment for Afrikaner refugees. As much as I try to remember the principle of charity
WP it's not easy to come up with anything other than privileging people of European extraction to explain such things.
That said, I don't think Executive Order 14398
WP and the various other orders around DEI can be explained in terms of restoring special privileges to the white majority in the U.S. unless we can make a rational argument that they would foreseeably privilege European Americans over African Ameicans, Asian Americans, Caribbean Americans, etc.
What you seem to want to do here is make the case for DEI by showing that the movement against DEI is rooted in racism, but there isn't any good reason to suppose policies will have good results so long as they have bad opponents. DEI policies stand or fall on their own merits, not on the despicability of their detractors.