VIVO Steel VESA Extension Mount... https://www.amazon.com/dp/B07MG8DCTL?ref=ppx_pop_mob_ap_share

Hey man, I made a post about this a while ago, which I'll copy here:

Hey, just a heads up that you can use a much cheaper arm than the HX, and it still works. I recently purchased an LG CX 48 and was faced with the decision of which arm to buy.. After doing extensive research and learning about the price and availability of the Ergotron HX, I decided to test my luck with a WALI arm I found on Amazon (https://www.amazon.com/gp/product/B07NLMLLT6/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1) combined with this VIVO VESA adapter (https://www.amazon.com/gp/product/B07MG8DCTL/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1). The display without the stand reportedly weighs 32.8 lbs, and the arm is rated for 33 lbs. Unfortunately, the VESA adapter, despite being the lightest I could find, adds 0.9 lbs of weight, bringing the total weight 33.7 lbs, which is 0.7 lbs heavier than the rated 33 lbs of the arm.

I am happy to report that everything works flawlessly. The monitor is mounted on the arm with the adapter and I'm able to move it up, down, side to side, tilt, rotate, etc. with very little effort. I had to tighten the tensioning screw a decent amount, but never felt like I was getting close to a limit or anything like that. I suspect there's a fair bit of tolerance at play here, both on the part of the arm's rating and on the part of the monitor's reported weight.

Anyway, I would highly recommend this combination as it's much cheaper than the Ergotron HX, it works flawlessly, and it's easily available on Amazon.

Cheers