I agree that the movement anti-cheat is way too strict. It's not as easy as flat out not allowing anything >140% unbuffed & unmounted, but it feels like the server tries to make sense of every single inch and every individual bit of movement each player performs, and sets them back if it deems the move invalid or illegal.
I have recently noticed this when I was struggling with internet connection issues. I was rubberbanding a lot, I could not move at all.
This tells me that the server only accepts legal and coherent movement events, and it rejects a scenario in which a player performs a legal set of moves while being disconnected for a very short period of time due to lag.
I would personally consider a solution that kind of "extrapolates" from the last known location of a player and checks whether a freshly received movement / location update is valid based on the player's speed and the time that passed between the last known location and the new one to be more efficient while preventing things like teleport hacking with comparable success.
It feels far too strict in one way or another, and I believe that there are better solutions that are just as effective, but less punishing for the general playerbase.
All that being said, if I were given the choice between this current anti-cheat and none at all, I'd still choose to have it. So annoying to watch sub-400k HP yolohunters teleporting straight across AB, ninjacapping every flag and mysteriously disappearing into the void whenever someone targets them ;_;