Sure thing, have in mind though that full support for the Dell UP3218K seems to be coming in macOS Ventura.
Right now in macOS Monterey each half of the monitor will be recognised as independent 3840x4320 pixel displays (or 1920x2160 HiDPI).
First we need to add the 3840x4320 resolution. The easiest solution is to install SwitchResX and use the 10-day trial (although seeing as you run Avid hardware and software you or the company should be able to cover the €14 license).
1. Download SwitchResX
2. Install it
3. Navigate to -> System Preferences
4. In System Preferences you should now have an SwitchResX panel
View attachment 2033472
5. Open it and click on the first monitor (DELL UP3218K), then click on Custom Resolutions and lastly the + sign.
View attachment 2033473
6. Add the 3840x4320 resolution (the HiDPI option will be added automatically) and reboot. SwitchResX ask if you want to save the changes, say yes.
7. After reboot go to -> System Preferences and open SwitchResX preferences
8. Launch SwitchResX Daemon (it should appear in the menu bar) and select either the full resolution (3840x4320@60Hz) or the HiDPI resolution (1920x2160@60Hz) for both monitors
The only caveat as mentioned up top is that it is recognised as two separate displays, so the menu bar will only be on one side of the screen.
To stretch applications over both "screens" you need to go to System Preferences -> Mission Control and deselect the option "Displays have separate Spaces". If you full screen an application it will only cover one side of the screen.
This should be the most straightforward way to obtain 8K60 but if this doesn't work I have two other things we can try.
I tried the Monterey Method it keeps saying invalid resolution after i restart when I try to add custom resoultion.
So i did a clean install of Ventura, and it still sees it as 2 separate monitors. Any advice?