The idea behind the OST at the end of today's #AOT episode was in fact good*:

After thinking about it a bit, it seems like they went with the drums of war to emphasize Willy's declaration. There's an interesting connotation with how Eren and Reiner are..
#AOTDeclarationOfWar https://twitter.com/MezuEko/status/1348348788184911874

pitted as two sides of the same coin. Both sides tell themselves they're free to act the way they did "because they were born in this world" as they justify themselves as the heroes of the story

But the irony here is that as soon as Willy reveals that-

#AOTDeclarationOfWar #AOT

King Fritz is the reason everyone is saved, he declares war on the same innocents who Marley provoked into acting in self-defense.

It's up to you to decide whether """"revenge"""" is justified or not (I don't think it is) but up until this point, Tyburs portrayed themselves as..

as heroes for trying to solve a problem they created.

It's all a false narrative. Propaganda.

You can hear the propaganda war drums as he declares war and portrays Marley as heroes again. It's all falsehood; the same as Helos who was a false hero. So the choice of OST here with the drums paints everything as if it was a stage performance, convincing the world of how..

"devilish" Eldians are.

Willy's narrative has been completed with this final act of him sacrificing himself. The drums only add to the -drama and fiction- of this propaganda

*With all that said, I still think it was awkward the way it was executed. It felt far too grounded for-

such a grand entrance by the Attack Titan. This, combined with how suddenly it cuts off at the end of the episode detracts from its importance, making this climactic moment feel very underwhelming compared with what preceded it.

Again, I found the episode perfect save for this OST use at the end along with a certain cut short conversation from the manga. So I'm not just blindly hating on it.