Where is your friend located? Assuming they're in the US, one option if they are unwilling/unable to build their own, is an assembly service from the likes of Micro Center or NewEgg. Typically the fee is in the ~$150 range, not insignificant, but allows you to select your own components - Outside of a few parameters, prebuilts don't allow for that.
Beyond that, take a look at NZXT's "BLD" service. They have some ready to go, or you can configure your own.
Example, their streaming PC - Ryzen7 3700X, 16GB of RAM, 1TB SSD and a 2070Super):
https://www.letsbld.com/streaming-pc
Spec'ing out similar, you'd be looking at right around $1300-$1400 so, in essence, they're just charging an assembly fee, yet have some preconfigured ready to go.