You are not familiar that C-14 dating is now a solidly young-earth dating technique?
The presence of C-14 throughout the geologic record is solid evidence that it is only thousands, not millions of years old. It is unreasonable to say we are wallowing in contamination with every measurement. The labs are not that sloppy. And it would have decayed away entirely in less than a million years otherwise, so the ubiquitous presence of C-14 in coal, diamonds, etc. is good evidence for their youth.
As for general dating, it relied on the unsound notion that C-14 production/decay ratios are constant and have been for a long time. Yet measurements of the rate of production and decay of C-14 in the atmosphere have always shown an imbalance going back to Dr. Libby's original work.
Once you realize that there was much more C-12 in the biosphere before the Flood (thus diluting C-14 at that point and yielding inflated 'ages' using old-earth assumptions) the C-14 data fits perfectly with young-earth interpretations.
After the flood most C-12 was buried while C-14 has continued to accumulate, leading to a telescoping effect such that there is little variance in the dates under 2500-3000 years between old and young-earth models.
"Earth age" estimates are based on Uranium decay, not C-14.