docsis 3.1 - not seeing greater than 40mpbs UPLOAD

so xfinity sends me reminders that i'm not taking advantage of my plan's speed. I signed up for gigabit a few years ago to get the 40mpbs upload after switching to a lower bandwidth plan for a few months that only had 5mbps upload (tried to save money from previous plan before that which was not gigabit and upload was too slow). i had to buy a new cable modem to upgrade the docsis 3,0 i had for many years once i went to gigabit since i needed docsis 3.1 modem for the new plan.

so my current plan is 1200/200 mpbs (increased from my previous gigabit plan of 1gb / 40 mpbs). an additional 200mpbs won't be realized in reality since there are not that many devices and concurrent use, and we don't pay for 4k streaming. but here's the thing - to go over the 1gb mpbs, i'll need a docsis 4.0 which is not yet mainstream. so why am i getting notifications i need to upgrade my modem when docsis 3.1 is the current and mainstream version up to 1gb mpbs?

if increasing bandwidth is the point due to concurrent usage, ok i get that. but it's worded / marketed as "speed" and not as "capacity"

also and if i do have a 200mpbs upload plan, i'm not seeing it as i do tests via xfinity speed test (and speedtest.net) occasionally. i'm not seeing it at all and it doesn't seem to be a docsis 3.1 limitation.even if it says "up to" i should/cloud be getting more than 40 with a 200mpbs plan, rigth? i don't get quite 1gb but i get to about 920-960'ish at night when only i am active in the network. i do my speed testing hardwired on ethernet cat 5e cable and routing is from desktop pc (has 1gb ethernet and 2.5gb ethernet ports, but i only use the 1gb) -> router -> cable modem.

below is what my plan says.