His criticisms of radiocarbon dating are interesting (while not completely supportive of his hypothesis). But it is an interesting rabbit hole to dig into; the relationship between radiocarbon dating and dendrochronology, and the attempt to get an accurate historical record of carbon isotopic composition over the last couple of thousand years is a surprisingly difficult problem, and in many cases has circular dependencies on known ages of artifacts.
I wrote a three part series where I summarize some of the more interesting pseudo-history theories that are out there:
https://blog.plan99.net/meta-historical-conspiracies-part-1-...
https://blog.plan99.net/meta-historical-conspiracies-part-2-...
https://blog.plan99.net/meta-historical-conspiracies-part-3-...
PTH doesn't really make an appearance because it's actually one of the less interesting theories. I don't believe these, but the facts the authors bring up to argue for their position are always interesting to learn about. Part 3 discusses some of the issues with 'scientific' dating methods and covers the circularity problem you discuss.
Sounds like he just played too much eu4.