I see only one problem with this.

It was almost two millennia between Eratosthenes measuring the circumference of the earth, and Magellan circumnavigating it.

I don't want to wait 1800 years for warp drive travel to be a thing, and that is a problem.

Of course, our advancements have, thus far, been exponential, so maybe. I can definitely hold out 18 years. 180 years is a bit iffy.

Edit. Others already knew or suspected it was round. Eratosthenes did the math.

It was almost two millennia between Eratosthenes measuring the circumference of the earth, and Magellan circumnavigating it.

I don't want to wait 1800 years for warp drive travel to be a thing, and that is a problem.

Of course, our advancements have, thus far, been exponential, so maybe. I can definitely hold out 18 years. 180 years is a bit iffy.

Edit. Others already knew or suspected it was round. Eratosthenes did the math.