Yes, WPA is a thing. Two consecutive batters lead off an inning by each hitting ground rule doubles to produce a run. Check out their WPA's for those specific at-bats. The second batters' WPA is significantly - no, tremendously - higher. But the two batters did the exact same thing and each double was as equally valuable as the other -- not an iota more nor an iota less. I tested this on the first case of back-to-back doubles to lead off an inning (I couldn't isolate for ground rule doubles, though I don't believe that should matter much) that I could find, and that was in https://www.fangraphs.com/boxscore.aspx?date=2022-08-08&team=Mariners&dh=0Monday's Yankees@Mariners tilt. Josh Donaldson led off with a fly-ball double and added .046 WPA. Gleyber Torres followed with a double of his own, and added .053 WPA. ( Donaldson held to see if the ball would be caught and didn't score.) For a little more context, Andrew Benitendi followed with a third double, plating both runners, and added .060 WPA.