Upload Speed Drops to <1mbps While Streaming to Twitch

Hello,

Thanks in advance for reading this long post. Whenever I am livestreaming to Twitch, it works fine at first - smooth for an hour or two - but then the upload speed drops to less than 1mbps and effectively ruins/ends the stream. I was browsing for some general support for this issue when I stumbled on this  Reddit post (https://www.reddit.com/r/Comcast_Xfinity/comments/lhpebk/upload_speed_goes_from_40_mbps_to_zero_while/) that details the exact same issue that I'm experiencing myself. 

Recently, I was experiencing a separate issue with my Xfinity internet service as it would randomly cut out and drop connection. This separate issue has already been addressed by Xfinity support, which included a technician visit to my home less than a week ago and a rental of an Xfinity-owned modem/router. The technician confirmed that all the cabling at my premises "looks good".

My hardware setup/configuration is as follows:

- The Xfinity modem/router is plugged in directly to the coaxial wall outlet using the provided Xfinity coaxial cable. The technician confirmed that this wall outlet is the only one receiving/sending data from the external cable line - no lines are split (the technician bypassed a split at the recent visit, which is what tentatively seemed to solve the other issue).

- My Win10 PC, which is running OBS (the streaming software), is plugged in directly to the Xfinity modem/router using a Cat6a ethernet cable.

- (I don't see how this is relevant, but I'll include it anyways) My Nintendo Switch is plugged in directly to the Xfinity modem/router using a Cat6 ethernet cable. The Switch is connected to the PC using HMDI cables and an Elgato capture card. The capture card is connected to the PC via a USB-C cable.

As another bit of information, this issue of the upload speed dropping occurred within the previous two hours of writing this post. When I visit the Xfinity Gateway to view both the system and event logs, no information has been recorded/logged today. In other words, my router's event log and system log is empty, even though this issue occurred. Other metrics from Gateway > Connection > XFINITY Network all look good (all pertinent downstream/upstream channels are locked and are within appropriate power levels).

Again, when I am streaming, it works fine at first; it is after an hour or two that this issue occurs and renders my livestream useless. I'd like to get this issue resolved ASAP, so I look forward to a timely response.

Thank you so much for taking the time to read my message, and thank you in advance for a speedy response.