Banning paid prioritization does not stop the ISP from prioritizing traffic for engineering reasons.
What it bans is prioritizing traffic because a content provider paid for their traffic to be prioritized. For example, Amazon would not be able to pay to have Amazon video prioritized over Netflix video, and Netflix would not be able to pay to have Netflix video prioritized over Amazon video.
Let's say I only watch video occasionally. My neighbor watches all the time. I consume maybe 5 GB a month. He consumes 1000 GB.
Me and my neighbor have the same tier of service, and are paying the ISP exactly the same amount.
You really don't have a problem if Netflix were allowed to pay my ISP to make sure that my neighbor's video watching gets priority, so he gets a great video performance, and mine sucks?
If you play video games, use realtime video services like facetime, or use a VPN for mission critical work, do you really want your traffic flows to be identical to something that delivers content to a rendering engine?
Different traffic has different requirements & performance characteristics. From a pure engineering perspective, this is a very poor decision and treating all traffic equally provides artificial and often unnecessary constraints.
I have never experienced any situation where prioritization has effectively become blocking.