Edit: Page 122 of the S-1. They are paying SOFR + 0.75%. So around 5.5% on the $20B.

I'll keep the below for integrity sake:

Well, i'm sure SpaceX bought Xai using some kind of prefered share/debt financing, but that's not to say that XAI had the original debt financing.

We can never know what the exact details, and the exact financing is on this debt. Maybe it's tied to Elon's Tesla Shares, Maybe it's tied to a convertible, maybe it is actual "loans" from a bank. Even at $9b in debt, and you naivly assume they are paying 10% (Def not 20% as OP claimed), you are paying $900m a year, for the entirety of xAi. Including that in the calculations to rent out the entire compute is folly. Not only is 900M not directly attributed to c1, cause it's split between c1, c2 and all the training runs, but you can never verify the interest. And even then, one month of this deal pays for the whole year of interest expense.

So go ahead and lower my estimate by 10%... doesn't make a difference.