I have 2 34 in. monitors and this is the best mounting arm I've tried so far - WALI Heavy Duty. I've tried and returned 4 others, including Ergotron, Amazon Basics, Huano, Vivo.

This MountUp version I kept and use it with a laptop stand. It just wasn't stable enough for the wide monitor, but is fine for my laptop (and probably would be fine with a regular sized monitor).

My current desk is a 55x28. I'm building a new one that is 84x36. I will be adding a third monitor arm once that is completed.