Try looking down a long flat road standing up vs face near the ground. As you move lower towards the ground you see less & less of the distant road. The change in what can you see is due to perspective, not curvature.

There has been many detailed curvature tests over bodies of water & a lot of debate as to what they show. Look up what others have done to show curvature or lack of curvature, if you’re curious, but look up both sides as they tend to both suffer strongly from confirmation bias.

The earth may or may not have curvature but would not be provable by the type of test you described.