The PCG family is somewhat harder to predict than Mersenne Twisters, but not nearly as hard to predict as cryptographic PRNGs. PCG’s author goes into some detail about it here https://www.pcg-random.org/predictability.html and the conclusion is:
“ The PCG family is designed with being difficult to predict in mind, and the default generators are not trivially predictable. But the primary design goal for most members of the PCG family is to be a fast statistically-good general purpose generator, and so by design they do not work quite as hard as most cryptographically secure generators.
“Most of the PCG output functions involve nonlinear operations and only reveal partial state, but as we saw from Knuth's truncated LCGs, that's no guarantee of that PCG generators can't be cracked.”
“ The PCG family is designed with being difficult to predict in mind, and the default generators are not trivially predictable. But the primary design goal for most members of the PCG family is to be a fast statistically-good general purpose generator, and so by design they do not work quite as hard as most cryptographically secure generators.
“Most of the PCG output functions involve nonlinear operations and only reveal partial state, but as we saw from Knuth's truncated LCGs, that's no guarantee of that PCG generators can't be cracked.”