22:50:57.975: [NVENC encoder: 'recording_h264'] settings:
22:50:57.975: rate_control: CQP
22:50:57.975: bitrate: 0
22:50:57.975: cqp: 15
22:50:57.975: keyint: 250
22:50:57.975: preset: hq
22:50:57.975: profile: high
22:50:57.975: level: auto
22:50:57.975: width: 2560
22:50:57.975: height: 1440
22:50:57.975: 2-pass: true
22:50:57.975: b-frames: 2
22:50:57.975: GPU: 0
22:50:57.975:
22:56:01.992: [ffmpeg muxer: 'adv_file_output'] Output of file 'E:/OBS Videos/2018-04-21 22-50-57.mp4' stopped
22:56:01.992: Output 'adv_file_output': stopping
22:56:01.992: Output 'adv_file_output': Total frames output: 9093
22:56:01.992: Output 'adv_file_output': Total drawn frames: 9110
These are good settings, its surprises me you found that quality to be poor. The only thing you might change is to record as .mkv or .flv instead of .mp4. If OBS crashes while recording a .mp4, the file is corrupted, but a .mkv or .flv will still be usable.
Other than that, all your settings are good.
Hmmm... maybe this?
22:49:20.982: fps: 30/1
You're recording at 30fps... why not 60fps?
Experimentally, try setting the CQP value to 10, and see if that helps. The filesize should be drastically increased, but so should the quality, if it was bad.. In what way is the quality low?
You're not downscaling, so this shouldn't matter, but this can be a problematic setting, if you were:
22:49:20.982: downscale filter: Lanczos
Their lanczos downscaler isn't much liked by most people. Try setting it to one of the other options. This should only matter if you're downscaling, but might as well set it.