To contemplate the dogmas frequently is fine, but if the premise is that there is a mythical component to the dogmas that waits to be discovered and discarded, then that premise is false by the definition of dogma.
For example, let us postulate that we don’t know if the donkey of Balaam really talked, or if it is a literary embellishment — a myth. If the Church were to construct the dogma about the donkey really talking, that would be an impossible dogma: one that does not arise from witness or from scripture. Such “dogma” would not need to be re-examined and cleaned up, such dogma would be a scandal.
Compare that to the dogma that Jesus rose from the dead. Of that there are independent witnesses and the scripture is clear on it. It is not a literary device: the gospel writer spent a lot of effort to point out that Jesus rose from the dead, was not a ghost or mirage, spoke, ate, was touched, was recognized by many, etc. This is why this is a dogma: it is both historical and necessary for the faith. That Nicea happened a long time ago only strengthens our faith in the historicity of the resurrection as Nicea was closer to the actual historical event. It is therefore absurd to re-examine Nicaea and theorize that perhaps something other than resurrection really happened and that the bishops at Nicaea really mixed myth with truth. People who “re-examine” Nicaea on that score exist, but they are properly described as non-Christians, and the dogma still stands as a whole despite them.
“but if the premise is that there is a mythical component to the dogmas that waits to be discovered and discarded, then that premise is false by the definition of dogma”
Where did you get the premise that there “IS” a mythical compent? The goal is to see IF there is an error (which there generally is not).
To the extent you say never to test dogma (not sure you mean this), well, I disagree. Dogma should be tested early and often.