How do I defeat Orwald in the “Blood of the Dragonfather” mission?

Hello, I'm attaching a file with save games. Unfortunately, the save where I had 24 black dragons was overwritten , but I have 2 save games with 23 black dragons and 18 black dragons. https://drive.google.com/file/d/1gvx...ew?usp=sharing - link to the save. File 321 contains 18 black dragons, and file 342 contains a squad and 23 black dragons.