I just bought the game, and I really enjoy it. I'm having an issue with it though. I'm not sure if it's a bug or something else.
I can't seem to maintain smooth performance with Project Warlock. GOG Galaxy's FPS counter says I'm getting a solid 60FPS, but the game doesn't feel like it's 60FPS. It stutters constantly. I was able to fix it temporarily by lowering the resolution by a lot, but obviously this is not an optimal way to play the game.
My computer is not top tier or anything, but it's able to play DOOM 2016 at a solid 50-60FPS on medium settings, so this game should be performing better than it is.
Got the same problem as you. It says that it is running at 60fps but it doesn't feel like that when moving and looking around. My computer can run DOOM 2016 at much higher framerates on max settings. And has no problems running the latest games at 60fps. So it's not your PC.