Which method is the best?
Professional says theres no right answer. Why?
Lump sum investment benefits individual who posses great psychological skills (to hold through economical cycle), has a proven “edge” against the market (backtested) and the money to do so.
Dollar cost averaging benefits those whom has fear (Price,risk of making a mistake,etc), and lower capital
There are more than one perspective to determine the best, but ideally knowing who you are will best define your investment strategy.
Some perspectives for you to ponder :