I think its similar to how no one at high school notices that Eve is a superhero - if you’re not looking for it, it’s easy to miss. For Allen, he’s doing a tour of planets that are outside the bounds of the known (to them) Viltrum empire. He goes to earth, sees no Viltrum technology/architecture or signs of a hostile occupation and is greeted by a single guy who fights him in space, he’s probably just happy that he doesn’t have to break atmosphere to do his eval because he’s got other planets to get to.

Why would they be based off Earth insects? They’re aliens, you’re overthinking this.

Because strength doesn’t directly correlate to having ripped abs. I like the change, having a dude who is built like a powerlifter/strongman gives a different dynamic to animated fight scenes rather than having an entire race of swimsuit models.

Like their entire race is built on being the best at being violent, no reason to not have some absolute tanks out there.

Unless Robert Kirkman is also writing What If, I seriously doubt it.