There are many ways you can prove the Earth is a "globe" or more accurately a sphere. But I'll give you one most people don't think of.

Draw a map TO SCALE that accurately depicts this "flat earth," including accurate distances between each and every city on Earth (I'm assuming we can agree on the distance between all of the cities as will be demonstrated via a simple Google search, yes?)

You will immediately find that there simply isn't any way to create a flat earth map to scale that accurately depicts the correct distance between each point as it exists in real life, for the same reason you can't create a flat map of the Earth without distorting parts of the map (take Greenland, for instance, which we know is almost always portrayed in flat depictions as being much more massive than it actually is).

That's all the proof you need. Not once has a flat earther ever managed to create a map accurately depicting distances between cities that you can measure using a ruler, for instance, because those distances are in reality superimposed on a curved surface, i.e., the Earth.

Just try posting a flat earth map which is supposedly drawn to scale and I would be happy to demonstrate how and where it is wildly distorted from what a true depiction on a globe would indicate.

After all, if the Earth is indeed flat, you should have an accurate map of what it looks like, right? So let's see it!