Well however thorough you think your understanding of “secular beliefs about ‘deep time’” are, your facts are not straight about what scientists actually do when they study deep time. First:
This claim is untrue. Or at least, it’s a misleading half-truth, and as they say, a half truth is a whole lie.
Fossils are used to date sedimentary rocks. Igneous rocks are used to date fossils. There’s nothing circular about that whatsoever.
Again, this claim is untrue. Radiometric dating does not make the assumptions that young earthists claim that it makes. I covered this point here:
We can cross-check measurement techniques whose assumptions are independent of each other, and we can make precise numerical testable predictions. These are sufficient to confirm to us that the measurement techniques work as described and are fit for purpose.
It is claiming that techniques for figuring things out do not exist when in actual fact they do that is a betrayal of a real lack of understanding of what science can and can’t do.