My fix was limiting the game to 60fps via Nvidia 3D Settings. (Check Image)
This seems to be a universal issue with older games running on new hard-/software (e.g. Skyrim being the preem example) where more than 60fps just cause more harm than good, unless fixed by mods. In Skyrim it's due to Animations and Physics being tied to 60fps.
I also tried turning off Threaded Optimization in Nvidia 3d Settings, no noticeable difference compared to just fps-limit, and it eventually crashed with a little spike in CPU and GPU usage (can't confirm the cause).
Simply running it in Windowed Mode (w/o fps-limit) helped as well, singificantly reducing stutters, but since I found no way for a borderless solution, this was no option for me. And since limiting the fps to 60 pretty much eliminated the stutters for me, it was an easy choice. Though as I understand, this feature only just became available in 2020 (pretty bonkers to think about it).
Additionally I patched the game.exe with the afore-mentioned 4GB-patcher, but haven't noticed any difference yet.
SPECS:
HP OMEN 15 Laptop + ext. Monitor (1440p 144hz Gsync)
OS - Windows 10 Home 64bit
CPU - Intel Core i7-9750H
GPU - RTX 2060 6GB (Mobile)
RAM - 16GB
SSD - OS+GOG
HDD - Game
