Took me some time but I finally found the encoding session hidden in all those errors. It's not horrible. There's some Rendering Lag/GPU overload. Doing the above should help but may not eliminate it all.
Load reduction:
Run only (1) monitor @ high refresh rates
Media Sources, there's a ton of them & I counted at least (15) using hardware acceleration. Only (2) maybe (3) of them in your main scene should be using it, disable it for all others & save the VRAM for something else as your system has plenty of free RAM available.
Scene Collection - Streamline it, nothing is free.
See Link
01:58:20.421: Last log entry repeated for 7 more lines
01:58:20.421: [rtmp stream: 'aitum_multi_output_YouTube Output'] User stopped the stream
01:58:20.421: [rtmp stream: 'aitum_multi_output_YouTube Output'] Socket send buffer is 2097152 bytes
01:58:20.426: Output 'aitum_multi_output_YouTube Output': stopping
01:58:20.426: Output 'aitum_multi_output_YouTube Output': Total frames output: 889474
01:58:20.426: Output 'aitum_multi_output_YouTube Output': Total drawn frames: 884600 (889612 attempted)
01:58:20.426: Output 'aitum_multi_output_YouTube Output': Number of lagged frames due to rendering lag/stalls: 5012 (0.6%)
01:58:22.251: Output 'adv_stream': stopping
01:58:22.251: Output 'adv_stream': Total frames output: 1058303
01:58:22.251: Output 'adv_stream': Total drawn frames: 1053238 (1058383 attempted)
01:58:22.251: Output 'adv_stream': Number of lagged frames due to rendering lag/stalls: 5145 (0.5%)
01:58:22.251: Video stopped, number of skipped frames due to encoding lag: 5155/1058338 (0.5%)
01:58:22.254: [obs-browser: 'YT Shirt'] Error: Blocked script execution in 'about:blank' because the document's frame is sandboxed and the 'allow-scripts' permission is not set. (about:blank:0)
01:58:22.254: [obs-browser: 'YT Shirt'] Error: Blocked script execution in 'about:blank' because the document's frame is sandboxed and the 'allow-scripts' permission is not set. (about:blank:0)
01:58:22.257: ==== Streaming Stop ================================================
01:58:22.332: warning: 2 frames left in the queue on closing
01:58:22.333: warning: 2 frames left in the queue on closing
01:58:22.873: Output 'Vertical Backtrack': stopping
01:58:22.873: Output 'Vertical Backtrack': Total frames output: 1058337
01:58:22.873: Output 'Vertical Backtrack': Total drawn frames: 1053227 (1058372 attempted)
01:58:22.873: Output 'Vertical Backtrack': Number of lagged frames due to rendering lag/stalls: 5145 (0.5%)
01:58:22.874: Video stopped, number of skipped frames due to encoding lag: 5354/1058370 (0.5%)
01:58:22.926: warning: 2 frames left in the queue on closing
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