17:40:03.935: Windows Version: 10.0 Build 17134 (revision: 765; 64-bit)
Windows is out of date and Game Mode is on by default and cannot be turned off without registry editing. Read the link at the bottom for info on updating/turning off Game Mode, which can in some cases degrade OBS performance.
17:47:05.739: adding 232 milliseconds of audio buffering, total audio buffering is now 301 milliseconds (source: Mic/Aux)
17:47:29.619: adding 232 milliseconds of audio buffering, total audio buffering is now 534 milliseconds (source: Skrivbordsljud)
Audio buffering going this high is generally indicative of system overload.
17:52:09.999: Output 'simple_file_output': Number of lagged frames due to rendering lag/stalls: 790 (19.4%)
GPU overload. Possibly caused by Game Mode mentioned above, which is designed to give your game maximum GPU resources, starving any other program trying to use the GPU (like OBS).
https://obsproject.com/wiki/GPU-overload-issues
17:52:10.004: Video stopped, number of skipped frames due to encoding lag: 3518/4059 (86.7%)
Encoder (CPU, in your case) overload.
https://obsproject.com/wiki/General-Performance-And-Encoding-Issues
After turning off Game Mode, I'd suggest capping in-game framerate and/or reducing canvas resolution to 1280x720 instead of 1920x1080 with scaling, if needed.