Man in 1850 they didn't have the means to speak to someone on Internet on the other side of the planet and set an experiment of comparison of speed of motion and direction of rotation.

Do you understand how the pendulum set at different latitudes gives proof of shape or should we in 2025 still reference to and experiment of 200 years ago without the ability of using it for a bit more? We have planes now they had horses.

On a sphere the pendulum rotation is related to the position on the sphere. We now can and did test it and earth is a sphere unless the aliens generate hidden forces to steer the experiment results and make us believe. Why should they do that?