Just as an FYI: if you have stock in a regular brokerage account, you can take out a margin loan in cash immediately. It depends on the broker, but IME it's fairly common (e.g. Fidelity does it).

Margin has a bad name as a "high risk" activity, but that's mostly when you have a concentrated position and are taking out a margin loan to double down on that concentrated position. Using margin as a bridge cash loan for a few days is a fairly low-risk proposition.