Towards the end of Shang Chi, Wong says to Shang Chi something to the effect of, "we noticed the 10 rings when you put them on" (I don't have the exact quote handy).
But the rings had been in use on earth for at least 1000 years, why wouldn't they have appeared on any sorcerer supreme's radar (or maybe any sorcerer - Wong isn't an SS but he is the one who approaches Shang Chi).
Dr. Strange says to Thor, "I keep a watch list of individuals and beings from other realms that may be a threat to this world." But these rings (though they are not beings, I think they would qualify), which clearly had an impact on the entire development of human history, seem not to have been known about.
Why would Shang Chi's wearing them have triggered the Sanctum's awareness while his father's use of them over 1000 years not have done so?