Humans don't just stop looking for something to worship once they reject organized religion lol

That gap will be filled unconsciously, for most in the modern age they worship the actors in Hollywood/Washington & find purpose in submitting their rights to the causes they promote.

No one is more easily manipulated than someone who thinks they are just a sack of flesh here to pay taxes, consume & die.

Most hate themselves and embrace victimhood

Simply provide a scapegoat oppressor in their neighborhood for them to fight while you consolidate global power.

A global empire cannot be achieved through force alone.

Any conscious, physical opposition will be met in kind, you need global threats to control/unite a diverse global population

Perhaps a climate catastrophe? A virus? An extraterrestrial threat?

Maybe even in that order.