[AB] Shaw Wide Open 150 Plus for Twitch Streaming

So - I'm a lowly gamer trying to make it as a twitch streamer. A pipe dream? Perhaps, but that's not what this is about. I've got Shaw Wide Open 150 Plus. It's 150 without the data limit. For an extra $20, I thought why not. Games on Steam rounding 100GB in some cases these days, it's a good thing to invest in. My download speeds are almost always consistently very good. Sometimes getting up to 180mbps; and that's using this sites own speed test, not one of those speed optimized sponsored speed tests from Ookla. My upload also appears to be within it's advertised limit (a bit higher at 16mbps actually). My problem is, the upload is also very inconsistent. If I try to stream to twitch, the stream *starts out* just fine. Absolutely fine. I stream to twitch at 6000kbps, and with a 15mbps rated upload, I should have absolutely zero problems doing this. However, eventually, down the line, whether it be 5 minutes in, 10 minutes in, or 2 hours in (it's completely random), intermittent spikes happen and the upstream to twitch will plummet down to 2500 or lower. I thought "maybe if I try setting it to 2500"...but no, if i do that it plummets even lower. Sometimes hitting speeds as low as 300kbps. On average, I drop about 6000 frames in a span of 3 hours, with it sometimes being as bad as 10,000 frames dropped. This happens no matter which twitch ingest server I try, and it doesn't happen on my neighbors telus internet with a 10mbps upload, so we can rule twitch being the problem out. I have a Netgear R7000 router with Advanced Tomato. Shaw tried to blame it, so I tried direct to the modem and had the same result. Shaw has sent a tech out to no avail, and now they are blaming the modem. I have the Hitron, and they've just mailed me out a Cisco DPC3848v. I highly doubt it's the modem, but I'll humor them. I'm convinced this is a congestion control / traffic shaping thing happening here, but even that is iffy because it doesn't matter *what time of day* it is. Whether it be 2am, 4am, or 8pm. Peak hours or not. It's always a crap shoot, which tells me it *can't* be congestion. Has anyone else had issues like this? I'm in Vegreville, AB.