Cash is king? Yes, but only for a small window of time when the stock market has crashed or perhaps some stocks in your watchlist has fallen to a level below its intrinsic value.
Yes, it was the Almighty for short period in 2000, 2008, 2016 etc. But for long duration in-between, cash is a drag and often trailing behind the returns from well-run businesses.
Perfecting the timing of the market cycle is the holy grail of investing. If you can side-step the down cycle correctly, own stocks on the up-swing and get off the bus at the peak, it will be super rewarding! But you have do all 3 things perfectly. Example, if your getting back to the market timing is off, you could be chasing the market and could buy in again at a higher price. As the market doesn't care one bit, it can go down the moment you are getting back into the game. Instead of being the smart chap you think you are, likely you will be the patsy at the table.
On the average over long period, market has returned about 6-7% per annum. Sit out and wait for STI to drop to 2000, could means sitting on cash for many years.
I say go for the middle-way. Stay invested but keep a sizeable warchest and fire on auto when big elephants appear. To me, sizeable is 30%.