Or you can request a block OTC trade with any of the major exchanges and they'll bite your arm off for your business. Zero slippage.

I work for a non-profit that has been trying since the beginning of January to get an account at an exchange that will convert a Bitcoin donation we received to USD. So far we have not had any luck, since many (most?) exchanges are not accepting new customers (or explicitly state that reviewing new account applications is their lowest priority) and those that do still accept new customers have multi-week wait times for opening accounts (at one exchange we've been waiting over 3 weeks ago with no reply yet).

As a result, we cannot "literally convert 100 Bitcoin to $1,000,000 USD in seconds", or even 0.001 Bitcoin. In fact, we can't even do so in 3 weeks (and counting).

Could you point us to an exchange that is accepting new signups and will verify an account for a 501(c)(3) non-profit organization within a day (or even a week)?