I used a second monitor arm for that screen as I found a double monitor stand couldn't have both with an ultrawide.
It's actually going to be replaced with a new stand as I find the current one too wobbly when extended out.
This is the new one I have coming - https://www.amazon.com.au/dp/B07BBHJK86/ref=cm_sw_r_cp_apa_i_vvkkFbBDQ0VBZ
I went with this one. I looked at a ton of mounts, but this one gave me the most in terms of height flexibility, and having two allowed me to space them apart enough so I can stack both monitors or swivel the smaller 27" one to portrait mode.
I went with two of these mounts.
I have this exact setup (AW3418DW & 2 24"). I just left the 34" on it's own stand and got 2 of these for the 24's on the side:
https://smile.amazon.com/gp/product/B07BBHJK86/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
Maybe buy a monitor arm that can support the monitor you will use for editing.
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