This is sequence of returns risk.
This is real risk when someone retires, and multi-year recession starts.
What we are looking for index fund like returns and drawdown like fixed assets.
One way to do it, it is created multi-asset portfolio with un-correlated assets (ie which do not go up and down in sync). Diversify and reduce the risk
Its possible to get least risk ( which is called minimum variance point) and still earn better than what fixed asset only investment will give you.
Or
Get almost index like returns with lower drawdown (which is called efficient frontier)
Portfolio theory suggests that more un-correlated assets you add in portfolio more you reduce risk (ie variability measured in terms of standard deviation).
However for individual investor it becomes difficult to manage so many indexes.
currently in India there are few funds which do multi-asset allocations. However, they trust on fund managers smartness to decide on how much to allocate on each asset class.
NPS is only one (which I know of) which uses fixed allocation, but it doesn’t use indexes.
My own retirement portfolio is simplified version of dream retirement fund with US stock market index as one of the components. I believe (rather pray) that it will be less volatile and still will give me index like returns (when I need money).