Should I sell ES3 STI ETF and buy ARKF at the next dip? How long should you hold ARK ETFs?

Currently holding some ES3 that I bought over the past few months, sitting at 8% gain and about 14% of my portfolio of ETF (VT), Robos and Stocks. Originally intended to hold for 4% dividends and sell when it reaches 3.3sgd. Based on the ETF history, that is about Mar 2021, but I anticipate opportunities in Jan when Biden moves in. I've been intending to put a lump sum into ARKF for value. Do you think it's advisable to sell off and hold cash, or stick to my original plan?