Hello
I don't know about the 57", but it is very stable with the 49".
Look on the Ergotron website to find the right one: https://www.ergotron.com/fr-fr...
Have a nice day

I would like to know the same thing, but elsewhere on the internet it suggests that it can just about hold it, but the tilt function will not work (or it will sag downwards). Ergotron are working on a heavier duty backplate to combat this, but no official date as yet.

I have the same question, please give me feedback as soon as you know more.
Theoretically, the 57" is still in the possible weight class, theoretically...