Rendering lag is GPU overload. Your main monitor is running 10-bit color, should be 8-bit. Also, run a test with all of your monitors @ 60HZ. 240/144/60 isn't helping here....
20:57:21.396: name=Odyssey G65B
20:57:21.396: pos={0, 0}
20:57:21.396: size={2560, 1440}
20:57:21.396: attached=true
20:57:21.396: refresh=240
20:57:21.396: bits_per_color=10
20:57:21.396: space=RGB_FULL_G22_NONE_P709
00:23:02.072: Output 'adv_stream': stopping
00:23:02.072: Output 'adv_stream': Total frames output: 737552 (738301 attempted)
00:23:02.072: Output 'adv_stream': Total drawn frames: 735922 (738397 attempted)
00:23:02.072: Output 'adv_stream': Number of lagged frames due to rendering lag/stalls: 2475 (0.3%)
00:23:02.072: Output 'adv_stream': Number of dropped frames due to insufficient bandwidth/connection stalls: 749 (0.1%)
00:23:02.078: ==== Streaming Stop ================================================
00:23:02.109: warning: 2 frames left in the queue on closing
00:23:02.109: warning: 2 frames left in the queue on closing
00:23:04.664: [mp4 muxer: 'adv_file_output'] Flushing final fragment...
00:23:04.664: [mp4 muxer: 'adv_file_output'] Number of fragments: 4726
00:23:04.749: [mp4 muxer: 'adv_file_output'] Full moov size: 7057 KiB
00:23:04.750: [mp4 muxer: 'adv_file_output'] Final mdat size: 9313618 KiB
00:23:04.750: Output 'adv_file_output': stopping
00:23:04.750: Output 'adv_file_output': Total frames output: 567044
00:23:04.750: Output 'adv_file_output': Total drawn frames: 566961 (567068 attempted)
00:23:04.750: Output 'adv_file_output': Number of lagged frames due to rendering lag/stalls: 107 (0.0%)
00:23:04.750: [mp4 output: 'adv_file_output'] Waiting for file writer to finish...
00:23:04.750: ==== Recording Stop ================================================
00:23:04.754: [mp4 output: 'adv_file_output'] File output complete. Finalization took 90 ms.
00:23:04.754: Video stopped, number of skipped frames due to encoding lag: 2480/738478 (0.3%)
See here for the 10-bit.