You are not a pilot nor will you be traveling to Antarctica by a ship. You will be given a job there but you wont be going there, they are selling you snake oil. You will most likely end up on uncharted island close to Antarctica
How are they going to find that uncharted island if it's uncharted?
Greenland, Northern Canada or Russia, thinking you are at the South Pole.
That should be easy enough to tell.
Is the sun up all day or most of the day in December or January? If yes, you're in the southern hemisphere, so you're not in Greenland, Northern Canada, or Russia.
When you stand facing the sun, does it appear to move across the sky from your left to your right, or from your right to your left? If the latter, again, you're in the southern hemisphere, so you're not in Greenland, Northern Canada, or Russia.
Easy peasy.
If the sun is up all day at any time during your stay, and it's after September and before March, you know you're at higher latitude than the antarctic circle.
If you can measure the elevation angle of the sun above the horizon at its highest and lowest point any day it's above the horizon all day (or grazes the horizon, in which case lowest elevation = 0°), you can estimate your latitude. The difference between highest and lowest elevation angle is twice your angular distance from the pole, so
Latitude = 90° - (highest - lowest)/2.
Here's a "handy" way to estimate angles in the sky without instruments:
https://oneminuteastronomer.com/860/measuring-sky/There are other ways to do this with a single elevation angle measurement, but those require additional information. The elegance of the above technique is that it's self-contained.