PUBG used to be not optimized very well, but I don't know for sure if that is still the case..
CSGO on the other hand is way more CPU bound, meaning the GPU doesn't make much of a difference in scores. It is possible you are looking at benchmarks of CPU's with higher per core speeds, which will yield better results in CSGO.
If you want to properly check if your GPU is performing as it should, you could run some GPU benchmarks (such as 3D mark, Cinebench's GPU benchmark and some games have a built in benchmark. Userbench is also an option).
At that point just compare your score to other 580's and you will likely get a better comparison to see if your GPU is truly under performing.