Is there a damage log by spell?

[Mhaeric]

You can base it off the potency in the tooltip, since your standard nukes display that instead of damage as well.

E.g. A single nuke might do 300 potency, and a DoT might do 150 potency plus 40 potency per tick for 24 seconds. Since ticks are every 3s, the dot has a total potency of 150 + 6 * 40 = 390. Compared to the nuke, that dot will do more damage if able to run for the entire duration. The actual damage numbers don't matter since they scale the same from the relative potencies which stay the same.

And no, there's no setting for displaying specific numbers for dots in the log. Even the third party parsers for the game have to guesstimate dot damage by extrapolating from the other data for this reason.