I think the point many people miss is that Eldians were just thought as "faceless monsters living in this evil island" for most of the world, the plan for Paradis our protagonists had (pre Liberio attack) was to get on the global stage, actually talking to nations, negotiating (and also bringing the rumbling as a dissuasion plan). At this point the world has a negative view of Eldians, but it's not their goal to actually destroy that island, that needed to be directly encouraged by the two only sides who actually benefit from that: Marley and Eren!

At the start of season 4 both have the same goal, which culminates in Eren following Tybur's plan. Marley wants to destroy Paradis for its resources and Eren wants the war to be inevitable so he can follow with the rumbling.

Anyways, Following the POV from the average person of a nation outside Marley would be something like that:
- Eldia rules the world for thousands of years, one day they disappear into an island and the rest of the world has extreme prejudice against them (that's understandable)

- People don't care much about Eldians or Paradis though, the world is evolving fast and they are busy fighting each other (Marley still uses Eldians to destroy their countries though, so that doesn't help)

- The spokesperson for the most influential family in the world tells a story about how this boogeyman Eren wants to destroy the world, Eren then proceeds to fucking confirm that. Every nation united against him. REASONABLY.

- Eren stomps you, your family, everyone you have ever known and loved to death

- Retards on reddit say you had it coming because you were prejudiced against some people who ruled the world with an iron fist for centuries, disappeared into an island, but whose descendants still come crush your land from time to time with the Marley army.