Calculating Player position based on another Actor?

Exactly. To this you need to add the logic for sorting distances and keeping track of their names in order (perhaps consider one float and one string array), preferably before filling the “distance array” and after the cast. On for each loop completed, update the scoreboard.

Also consider playing with the tick interval, have it update 0.33 or so. Enough so players can’t tell it’s lagging a couple of frames.