How does the Daily Loss work?

It is a total loss from midnight.
Daily loss = total profit of closed positions + current floating profit
Daily loss % = 100 * Daily loss / Initial account
This metric is reset at midnight.
The corresponding validation criterion is Maximum daily loss %. It has a default value of 5%, which corresponds to $500 for an initial account of $10000.
The “Maximum daily loss %” is relative to the Initial account. That is. 5% will be $500 for the complete backtest.

How does the Max Loss work in the FTMO Robot?

This is the maximal loss relative to the initial account. It is not a Drawdown.
The corresponding validation criterion is Maximum loss %. It has a default value of 10%, which corresponds to $1000 for an initial account of $10000.
Maximum loss = Initial account – Minimal equity
Maximum loss % = 100 * Maximum loss / Initial account