Could one use robos as a way to do dividend investing so as to drawdown each year for spending? Say if I invest a lump sum of $500k on robo and would then draw out $25k (5%) yearly for daily expenses. Any advice?

The idea of passive investing is putting your money in funds and not do anything with them. Thus, I hope u refined your question.

Roboadvisor helps you to reinvest your dividends. The idea of robo advisors is to do a DCA and ignore them. If you would like to withdraw yearly, nothing wrong with that but you may sell at a lower price.

You mention that you need the funds for daily expenses. Here are some approaches :

1. Have a higher emergency funds ( it sounds like you have problem with your cash flows)
2. Invest into dividend stocks such as banks or Reits. The annual dividend then can be your expense

In conclusion, look at your current and near future spending(3-6months),
Allocate emergency funds, the balance will then be your investing funds