NieR: Automata is a pretty damn good game, but as is tradition for any AAA game its PC launch was mired by technical issues. Bugs and glitches aside, the biggest problem most people talk about is the performance, which for some configurations can dip down all the way to 20 FPS despite the hardware being up to par.
If you're one of the players suffering from this issue I might just have some good news for you! The recently updated and completely unofficial FAR patch (Fix Automata Resolution) has added a new option that controls Global Illumination, which if tweaked can result in a massive performance boost for a comparatively tiny decrease in visual fidelity.
I haven't tried it myself, mostly because I'm one of the lucky ones that has absolutely no problems with the PC port, but according to the vast majority of comments on Steam it appears that the fix does indeed work. If you would like to give it a try for yourself you can find the automated installer over here, and for those of you that prefer to do things manually you can pick up all of the files on Github. The installation process is as simple as dropping the files into your NieR: Automata folder, and then briefly messing around with the settings to find values that suit you. Good luck!