The issue may be from your OBS PC, but is equally probably as it has NOTHING to do with OBS PC [so any monitoring on your PC, won't be relevant. And You need to monitor at OS level, not OBS]. Start at OS level and make sure security software, or a plugin, or other unrelated software (cloud sync?) isn't your culprit. Once you have eliminated OS as source of bandwidth contention, most likely, Either your WAN bandwidth isn't sustaining what you are sending from OBS, or something else is using that bandwidth. Now, whether these are caused by hardware issues, or just utilization (traffic) can't be determined without monitoring. And there are some other odd-ball possibilities, but I prefer to start with the more likely causes, as that tends to get to resolution quicker