If the stock market corrects by 40% or so over the next 2-5 years, then so will $GERD... Are you sure that an equity ETF portfolio is right for your scenario?
It's difficult to say at the moment, overnight money is almost no longer worthwhile, and you can't rely on money market ETFs either, as the interest rate could be adjusted at any time. Fixed-term deposits would still be an option, but that's not a great idea either.