SB6121 upgrade question - Time Warner Internet

This question is about "SB6121 upgrade question", with Time Warner Cable internet and apps. I'm sure this has been covered to death already, but here we go:

I just switched from TWC Extreme internet (50/5) to Spectrum Internet which I believe is 100/10 in Dallas. I have the SB6121 owned and see that it is only recommended for the 50 mbps plans but I am getting up to 118/12 when speedtested on multiple sites and multiple devices (direct wired and wireless). Every now and then it seems to bottleneck and top out at 38/12.

My question is: would upgrading to the SB 6183 or SB6190 help alleviate the occasional bottlenecks when there is congestion/multiple devices running/etc? I know the 6121 has 4 channels and perhaps having the extra capacity would help things run more smoothly? When I'm getting 100+ is it just running at max and struggling to keep up? I normally have 2 laptops, 1 desktop, and 4 or 5 phones running at any given time with anything from online classes to facebook to factime to netflix all running at the same time in the evenings.

This topic covered SB6121 upgrade question, and TWC cable internet service.