Making any investment yearly at the same time is attempting to time the market, it's a bet that the market will be lowest at that point vs the rest of the year.

Except when we’re talking about accounts with maximum annual contributions (e.g. IRAs).

As I mentioned in my original comment, assuming one subscribes to the philosophy that in the long run, time in the market always beats timing the market, then logically it follows that one is better off investing a lump sum as early as humanly possible (i.e. as soon as they have the capital available to invest). If somebody doesn’t subscribe to this philosophy, then of course we’ll never agree on investing the lump sum up front vs DCA.

In the context of investing a lump sum all at once versus DCA, DCA is a form of timing the market. The only time DCA isn’t a form of timing the market is when the capital is only available in certain intervals (e.g. disposable income from wages).