Speed of Light isn’t c. Or is it?

There are numerous things in physics which we are not certain about. But the speed of light? We are so certain about it that we even defined the length of 1 meter using it. It is the distance traveled by light in 1/299792458th of a second in a vacuum.

As discussed in the above video by Veritasium, no one has ever measured the 1-way speed of light. We have always calculated the two-way speed. Therefore, if light travels at different speeds in different directions, it would imply that our value of c is incorrect.

Due to the restraints provided by general relativity, it is impossible to calculate the one-way speed of lights, the problem being syncing clocks.

The problem being interesting, I have thought about it. I am sure that we have the correct value.

Our Universe is the distance from which light has traveled to us since The Big Bang, roughly 13.7 billion years ago, or, in other words, everything we can see from the earth belongs to our universe.

If the speed of light is c, then our universe is a perfect circle centered on us with a radius of 13.7 billion years around us. If it is not, then we are not the center, but towards the edge:

We can measure the distance between us and heavenly bodies accurately using redshift or parallax. If we can find the furthest objects we can look at from different directions, we can compare the distances. If they are roughly the same, light has traveled at the same speed towards us.

If there was such a phenomenon, I think it would have amazed physicists and we would come to know of it, and since I don't have such information, I assume we are in the center of our universe, and the speed of light is c.

Since we have NASA Deep field images (images of celestial bodies more than 13 billion light-years away) from various directions, I, using my second argument, can prove c at a precision of ±3349345 m/s, as light has been found in almost every direction from a distance of 13.3 lightyears.