I really think this is the wrong framing for progressives. You're protesting a narcissist troll with an ego so massive it affects the passage of time. He's not styling himself as a king, so he can plausibly reject the concept on its face, and he probably enjoys the warm, itchy feeling it creates in his butt thinking about all the people calling him a king. So he gets to wriggle in his chair with a wry smile and say "I never said 'King Trump', but you go ahead." His supporters will revel in your frustration, because they know you're not willing to match their level of chaos.
You're dealing with a narcissist. There's no shame or logic or reasoning that will convince him or his followers to abandon their power. We need to take it from them.