So when I say radiometric dating, I'm specifically referring to U-Pb, Ar-K and Rb-SR rather than C14 as I think these are more accurate when it comes to corroborating an older earth. I've heard people mention how all of these methods rely on certain assumptions, even isochron dating, which is why they might not be as accurate as we may think. I'll list a few I've heard parroted:
Assuming starting parent-daughter ratios
Assuming its a closed system
Assuming the decay rate is constant
Here's a creationist link that expands on these 3 (disclaimer--I'm not a creationist, I know AiG is pretty much all pseudoscience, but its difficult for me to find secular sources that provide as in-depth of an analysis as they have): https://answersingenesis.org/geology/radiometric-dating/radiometric-dating-problems-with-the-assumptions/
So any help figuring out how important these assumptions are in relation to determining an accurate age for the Earth would be appreciated!