You gave me flashbacks to 2010 when I had used ADSL and thought 128 KB/s download was the best thing ever for downloading MP3s. And as you mentioned, using up all upload bandwidth effectively DoSed everyone else on the network, though in my case, any single person downloading also slowed down everything else to a crawl. I must have had less "downstream channels" (or whatever the DSL equivalent is) than your setup.
My current internet connection uses DOCSIS 3.1, but I can't recall any resource contention even if I have several computers trying to upload simultaneously. Not a big fan of asymmetric speeds, though, but apparently DOCSIS 4.0 (which is being finalized this year) gets us closer to symmetrical speeds.
That's not viable for me, as my subnet router is on the far side of my DSL connection. There's absolutely no way for me to filter incoming packets before they traverse my downlink. And as far as I know, there's no easy way to get all of my machines on my static subnet to coordinate traffic shaping.
