Good choice. If "hi spec", not sure about any great bargains. Dell is known for higher prices on upscale components. You might check Dell Outlet. If you can find the machine you want you'll likely save $400-500 at least... will full 3-year warranty same as "new".
What CPU are you planning?
I just checked Dell Outlet... no T5820s available. So I checked the retail screen and found T5820, 16GB RAM, 2x Nvidia T600 (dual port cards). It has an 256GB NVME boot drive. If just for trading, 256GB should be more than enough. Price = $1850.
I checked the Passmark on the "entry" CPU.. i9-10900x = ~22,000... checked on the i9-10980XE ~33,000. However the "single thread" performance on both is about the same. So unless you're sure your software will use more than 10 cores, there's no benefit to paying the higher price for the 10980XE.
Good Luck!