The flaw in your logic is that your map of the globe is wrong, so you see inconsistency.
Latitudes and longitudes are pretty easy to measure, and no matter what shape the earth is, longitudes at least are definitely going to be correct. So when two locations 180° of longitude apart have a high tide at the same time, and the two locations halfway in between have a low tide, it's good, solid data. No inconsistency there.
You cannot say that the Earth is flat because tides don't match what we would expect to see on a globe with gravity.
Now it's right.
Put a bit of study in man. Look up some records, go through some data. Oh, and try that saucer thing! If you can get sloshing that gives you consistent tide-like motions with peaks 180° apart and troughs in between, I'd be very interested!