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To know whether the sun revolves around the Earth or the Earth around the sun (or whether their movement is more complex), you need to be in a NON-MOVING frame of reference, which is axiomatically impossible according to Einstein.

You are wrong. You should definitely learn more about this topic. According to Einstein, the relativity of motion applies only to bodies moving at a constant speed in a straight line. In this case, it is impossible to say whether one body is moving away from another, or vice versa. There is no absolute motion. But if a body is moving with acceleration, it is a completely different matter. If you were inside a ship that is moving at a constant speed in a straight line, and you had no connection to the outside world, you would never be able to tell whether the ship is at rest or in motion. However, if the ship is moving with acceleration, you would be able to tell with certainty, even without instruments; you would feel it inside the ship (you would be pressed against the wall). Therefore, motion with acceleration is absolute. In particular, when one body revolves around another, it experiences centripetal acceleration, while the body around which the rotation takes place does not experience such acceleration. Therefore, it is always possible to accurately say which body is revolving around the other. I hope I have explained this clearly. If you doubt this information, I advise you to study the theory of relativity more carefully before explaining to me that it is not so.

At the same time, you can also use a MODEL that the sun revolves around the Earth (for example, in marine navigation).

This model is acceptable in marine navigation because the physics of celestial bodies is not important there; it is only important to determine the correct direction.