I remember hearing even some high specced pcs were having issues and you had to essentially be lucky that you had a configuration that they had the time to optimise for. Just having the best gpu wasn't enough, for example

True, though that shouldn’t give anyone dev or publisher the right to release a broken game on consoles because it works on PC. Either postpone the PC release date until the console issues are fixed, or release as a PC exclusive until the same. Part of the reason the game was so successful with phantom liberty is that they stopped previous gen console work so they could only focus on hardware that could actually support the game. As with many devs, their partnerships fucked them, getting pressure from Sony, MS, and Nvidia to release the game before it was a polished product

I tried playing on the lowest possible settings with a 1070 and averaged around 14fps :/

I still finished the game because it was awesome, but haven't revisited it ever since.

I played it on a pc that was ok at the time and the physics engine glitched out so things that were supposed to be sitting still on top of/next to each other would randomly collide and sometimes fly off. Still had fun with the game though.