You are significantly overloading both your renderer and your encoder:
18:48:24.263: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 2222 (34.7%)
18:48:24.264: ==== Recording Stop ================================================
18:48:26.540: Video stopped, number of skipped frames due to encoding lag: 3301/3394 (97.3%)
1080p60 while capturing a high motion application on a single machine setup can be challenging.
The rendering lag indicates you need to reduce GPU usage of R6 by some method to make sure that GPU utilization stays between 90-95% so that OBS has access in order to render frames. One out of 3 frames is being dropped because when OBS tries to render a frame, it cannot access the GPU, so the encoder get a duplicate frames until the GPU can render a new one. This appears as stutter, and 34% is very, very noticeable. The easiest and fastest way of doing this is capping the in-game framerate. Next best ways are choosing to stream either 1080p30 or 720p60 instead of 1080p60.
You are also overloading your encoder. I'm not familiar with the AMF encoder or its settings, but 97% skipped frames indicating that you are asking it to do significantly more than it is capable of, or that there is a significant problem with your GPU's operation.
