How many times have I said this...
You will not find a study showing the Earth is flat, as nobody has the time to waste writing up such a thing, and no group has a reason to publish such a thing. The only reason you can find works that suggest the Earth is flat/concave is because people have gone out of their way to spread misinformation. Cartographers have mapped the planet several times over, and produced maps that fit onto a globe. The reason they then don't go out and produce a deep scientific report saying 'The earth is still round' is because nobody would care. Several groups have put objects up into space, but they then don't go out and publish a report explaining how this proves that earth orbit still exists, as everyone expected. You can even go out and measure the curvature yourself, go out and map the distances between the continents and find it fits a globe, aside from the fact that I know regardless of what you see you'll just come back saying you see a flat earth.
I've no idea why you can't accept the fact people have mapped the Earth, or seen it from space, or made reliable measurements using a RE model as suitable evidence. Nobody's going to do a scientific study to check the Earth's still round, any more than they're going to do one to check the Sun is still there.