Have you gone through this in detail?
https://obsproject.com/wiki/Dropped-Frames-and-General-Connection-Issues
if yes, then next step is NOT OBS related, but general network throughput testing
in general -
1. use a Wired Ethernet connection with ABSOLUTELY no other devices on network for preliminary troubleshooting .. no not kidding. do not advance to step 2 until doing this as described
2. Assuming you have adequate bandwidth allotment to waste, do a large (multiple GB) file transfer to a fast upload site and monitor sustained throughput. If throughput varies greatly, and drops to a low level, then working with ISP may be required
3. As with video, audio, etc - basic troubleshooting/scientific method dictates to minimize variables.. so take OBS out of the picture [don't use it, and test network, etc without streaming]
Also, lots of folks have poor PC hygiene and an educated, thorough cleaning up the OS rarely hurts [whether this applies to you or not, I wouldn't know, and the OBS log won't indicate anything other than whether you've overly postponed Win10 OS version updates
And in case oyou hadn't noticed, it appears your log didn't link to this post