You absolutely can Begin and End in the same location on a Level Plane when you travel in a circle.
Dude.
Let's make this simple.
Here's Gleason's flat earth map, which I assume you think is pretty accurate. I've highlighted three cities: Sydney, Australia, Anchorage, Alaska, and Santiago, Chile.
According to that map, the distance from Santiago to Sydney is roughly (eyeballing it here) twice the distance as it is from Santiago to Anchorage. You'd essentially have to fly through Anchorage to get to Sydney if you left Santiago and went in a straight line.
So in this flat earth world, the distance between Santiago and Sydney is roughly 2x that of the distance between Santiago and Anchorage.
But here's their actual, real-world, distances between those cities. Use
this calculator.
Santiago --> Sydney: 7,060 air miles
and
Santiago --> Anchorage: 7,863 air miles
So it's 800 air miles LONGER from Santiago to Anchorage than it is from Santiago to Sydney. Which is IMPOSSIBLE according to this flat earth map.
Now to test this look at the fastest real-world flight times of actual flights, using google flights.
Santiago-->Sydney: 15 hours, direct flight
Santiago--> Anchorage: 27 hours, but it has two stops, one in NY and one in Seattle
Now before you go crazy about the fact that there are two stops compared to a direct flight, understand that in this flat-earth map, neither NYC nor Seattle are actually very far off the straight line from Santiago to Anchorage. And the layovers are 4 hrs, 35 min in NY and 1 hr, 20 min in Seattle, so about 6 hours total.
So you take the added slight zig-zagging and the near 6 hours of layovers into account, and let's say a direct flight from Santiago to Anchorage should really be about 17 hours.
17 is still more than the 15 hour direct flight from Santiago to Sydney.
But according to the flat-earth map, the distance from Santiago to Sydney is about TWICE as long as it is from Santiago to Anchorage. So shouldn't a direct flight (going the same speed) from Santiago to Anchorage be about HALF as long as a flight from Santiago to Sydney?
Why, yes. Yes it should. But it's not.
Not in the real world, where real people live.
It would take you, a flat earther, longer to fly direct from Santiago to Anchorage than it would to fly direct from Santiago to Sydney. For real. Not make-believe. Not a conspiracy theory. But for real. And it's all because the distance between Santiago and Anchorage is actually GREATER than the distance between Santiago and Sydney, which is the exact opposite of what the flat earth map says.
You can live in your make believe world of the flat earth, but you do so while living in the actual, real world like the rest of us, where the distance between Santiago and Sydney is actually shorter than the distance between Santiago and Anchorage. Your beliefs can't change reality.