This is what soft tissue looks like after six thousand years:
Complete carcasses. Masses and masses and masses of fully sequenceable DNA. If the Earth really were six thousand years old, we would expect to find T-Rex carcasses in at least as good a state of preservation as that all over the place. We have never found so much as one that comes even remotely close.
There’s something you need to realise here. The age of the Earth is not “supposed” and it is not “assumed”; it is measured. It is measured on the basis of processes whose rates have been measured and whose initial conditions have been measured. The extent to which these rates and initial conditions could have varied in the past has also been measured. And I’m sorry, but there are ways in which these conditions can be measured that do not require you to have “been there,” and that do not require you to make blind assumptions of “uniformitarianism.”
And I’m sorry, but measurement is a “hard” science. It has strict rules, principles and standards that must be adhered to. Rules, principles and standards that have nothing whatsoever to do with “naturalism” or “secularism” or “uniformitarianism” or any other weasel word ending in “ism” that you may try to throw at them. And it is not reasonable to claim that anything is evidence for a young earth unless it sticks to those rules, principles and standards.
Would you like me to explain what those rules, principles and standards are?