Don't use a non-CSPRNG if you worry about adversaries. CSPRNGs are only ca. 10 times larger and roughly as fast if you can use SIMD.
According to [1], you only need 4 outputs to predict xoshiro. Predicting PCG is a bit more difficult, but still on the level of "exercise for cryptography students" [2].
Comments
Don't use a non-CSPRNG if you worry about adversaries. CSPRNGs are only ca. 10 times larger and roughly as fast if you can use SIMD.
According to [1], you only need 4 outputs to predict xoshiro. Predicting PCG is a bit more difficult, but still on the level of "exercise for cryptography students" [2].
[1]: https://www.pcg-random.org/posts/a-quick-look-at-xoshiro256....
[2]: https://hal.science/hal-02700791/document