I don't know about where you live, but by far the lowest latency option for me is symmetric gigabit. And my options jump from 200/20 to 1000/1000, and 200/20 was for sure not enough for everyone to stream and video chat at the same time.
My wife and I occasionally work while we're visiting her parents. We get away with doing teams calls at the same time on a 15/15 wireless link. Congestion only starts if our son downloads something while watching YT, while we're on calls.
It surprised me, but it works. And despite my 1125/50 connection at home, it surprised me how easy it was to adapt to lower speeds.
That being said, given the option I'd say 200/20 is my preferred minimum.
Multiple video chats can saturate 20 Mbps up, but if they offered 200/200 it would be more than plenty. Them not offering reasonable plans in between a little to low and way too high doesn't mean that it couldn't exist, it just means that they aren't offering it, likely because they have paid your local government to prohibit any competition, allowing them to force a large portion of their customer base to use a more expensive plan than they need, because no one else is going to offer a reasonable one.
