As a Flat Earther you shouldn’t use Google Maps and this is why.
As you can see from the curved lines in the map section below, Google Maps uses a globe to calculate the distances between two points. If the earth is flat, these distances are wrong.
At first glance, the distances should be too long since the curved line is longer than the straight line between two points. In fact, Google Maps gives the distances too short.
To show that, I drew the cities of Dublin, Madrid, Moscow, and Rome on a chart using the coordinates. I drew circles around Moscow with the diameter of the distance to the cities of Dublin, Madrid and Rome. No circle runs through the dot of the respective city, all circles are too small. You can do it with all other cities the result would be the same.
If you want to prove that the earth is flat, you shouldn’t use Google Maps distances. You must calculate your own distances because with wrong values your proof will fail and show that the earth is a globe.
The alternative, of course, is to accept that the earth is a sphere.