Live streams from cameras attached to the international space station. The curvature observed by a weather balloon is consistent with what one would expect for a sphere of the earth's size. It is very mild and difficult to tell by looking at images by eye. One must get just a bit higher up then they go before things become more obvious.
The company I work for has had payload on rockets going to the ISS, so maybe I've had access to camera feeds others don't typically see. Regardless, the earth is a sphere based upon all available quantitative and qualitative scientific data.
As I have said all along, I mean no disrespect, and do not seek to change anyone's mind. I will say the perspective you have from the ground is insufficient to observe the curvature, and that statement is provable by math. Believe what you would like. Have a great one.