I'm suspecting your PC is overloaded... (Task Manager showing 90+% CPU sustained). Real time video encoding is hard work. Modern tablets, etc have dedicated hardware for the video encoding. Your system does not have such and as such I'm guessing is struggling. I'm also guessing matters are helped by being on a HDD instead of SSD
You'll note I'm not giving you step by step below. You can look up the step by step as easily as I can, so I'll let you. And I'm no expert, so ymmv. Good Luck
16:04:32.438: CPU Name: Intel(R) Core(TM) i5-4590S CPU @ 3.00GHz
That is an old CPU for real-time video encoding. It is enough, but only with optimized settings for both OBS, and that you have a clean running Operating System (no unnecessary programs and services running, understanding RAM (& CPU) usage and how to monitor (ex Chrome can be a RAM hog)
16:04:32.438: Windows Version: 10.0 Build 19043 (release: 2009; revision: 1083; 64-bit)
why still running on an old release?
16:04:32.438: Windows 10 Gaming Features:
16:04:32.438: Game DVR: On
assuming you aren't using this, turn it off
16:04:33.094: video settings reset:
16:04:33.094: base resolution: 1920x1080
16:04:33.094: output resolution: 1280x720
rescaling takes extra CPU. assuming you plan to stream at 720p, and you aren't going to record at 1080p, I'd recommend dropping base resolution to 720p to match output resolution. Yes there are implications to this, but to try ang get OBS working on really old CPU, you will have to compromise. There are others much better than I regarding settings for older systems
16:04:33.094: fps: 24000/1001
Do you have a specific reason for going for 24fps? If you are streaming via FaceBook or YouTube, you are probably better off with 30fps
16:04:42.206: [ffmpeg muxer: 'simple_file_output'] Writing file 'C:/Users/User/Videos/2021-07-12 16-04-42.mp4'...
As the program tells you - do NOT record to MP4. period. Only those that know exactly why not to, and have a very stable system can reasonable even consider breaking this rule