This entire episode has Moff Gideon’s fingerprints all over it. Although he was believed to have been headed to a New Republic War Tribunal, rumors abound that he has escaped. His former communications officer, Elia Kane, just so happens to be stationed in the same Amnesty Program that his former asset, Dr. Pershing, is in, and she lures him into having his mind wiped by the New Republic. It certainly makes one believe that Gideon is pulling the strings here. But could he be the one who has marshaled this force against Bo-Katan?
He certainly has the motive. As the one responsible for the Night of a Thousand Tears, he seems to have a personal vendetta against Mandalore and its people — Bo-Katan in particular. She was also part of the force, led by Din Djarin, that boarded his cruiser, took his Dark Troopers, arrested him, and sent him to the New Republic. He certainly has added reasons there to want to make Bo-Katan suffer.
But he didn’t even have a Star Destroyer at his command before. Where would he have gotten a fresh resupply of TIE Interceptors and Bombers in a way that the New Republic wouldn’t notice? Perhaps he’s working for a higher power now.