It isn't part of your "circle." The theory behind and techniques of radiometric dating are independent of fossil finds.
But all forms of radiometric dating have been shown erratic and wrong.
You have some evidence that the theory of radioactive decay is wrong?
Not the whole theory, just the conclusions based on faulty assumptions. Take Mt Ngauruhoe in NEW ZEALAND where Rock known to formed from lava flows in 1949 were dated to be 300,000 years old. In Hawaii rocks from a recent lava flow was tested by various radiometric methods all with vastly different results. Even more startling was that one end of a particular rocks was a million years older than the other end of the rock according to one of the radiometric dating methods used. There have even been samples that aren't created yet according to the assumptions of the tests.
A better interpretation of the lab results might be that the ratios of parent to daughter reflect processes not age exclusively. The amount of the parent and daughter element present at formation is not known, the processes that might have influenced ratios are not known (i.e. leaching). The assumptions are dangerous and do not pass scientific muster. They are not verifiable, repeatable or observable. The assumptions must be taken on faith. But, when confronted with the fallacy of real tests the scientific community has refused to retract. Their religion is too important to give up based on real science. Besides they would hate for Christians to be right, again!