Kaido and Big Mom in part created their alliance because they feared the looming invention by Vegapunk. They tried to utilize science themselves, by having Caesar make them SMILES, artificial giants, gas weapons and so on. Blackbeard is a long term planner. He has seen the Seraphim with his own eyes now. How will he try to fight the lunarian warlord clones? I think Blackbeard recruited Moria. He will defeat Shanks and give the Redhair Pirates shadows to him. That zombie army will then compete with the Seraphim. We won't get Shanks vs Mihawk, the WSS doesn't want to fight a cripple, but we might get Zombie Shanks fighting the Mihawk Seraph.
I made a video about it:
I made a video about it: