Streaming itself is very little load on the computer. real-time video encoding is VERY computationally demanding so simply running OBS or similar software is what is having the effect. Running in OBS in Studio Mode doubles the rendering workload. Some of your OS settings are causing extra workload.
And you have the PoS StreamElements plugin puking all over the log and causing who knows how much havoc on your system
Thanks for log but you appear to have overlooked actually recording or streaming, so the log is incomplete
I recommend monitoring hardware resource (CPU, GPU, RAM, Disk I/O, etc) utilization [for ex. using Task manager’s Performance tab and/or Resource Monitor] to see if your system is being maxed out with your settings
See
https://obsproject.com/wiki/General-Performance-and-Encoding-Issues and
https://obsproject.com/wiki/GPU-overload-issues
And recognize that even not maxing out resources doesn't mean there aren't hidden bottlenecks. Not sure these will imapct you but look into Win10 settings regarding Game DVR & Bar, as well as HAGS. Then look into OBS settings Psychovisual Tuning and Lookahead with possible system impact with those (possibly worth testing).