How did you get it in a custom dimension? I'm almost tempted to just put two of my current desk back to back to make it deeper, would probably be much cheaper than 2k, but then again, they're not standing desks.
If you want a cheaper option you could buy an IKEA Karlby Countertop that's 74" x 42" [1] and mount it on the legs yourself.
[1] https://www.ikea.com/us/en/p/karlby-countertop-for-kitchen-i...