I also absolutely miss this option. I just had a puzzle, that made me pondering, while my opponent didn´t find the solution either, but then advanced in solving the ones to come. Finaly I didn´t learn to solve the puzzle.
And furthermore I would love it, if it were easier in the puzzle rush mode to learn resp. try again the puzzle one did wrong. It´s rather complicate and demands too much clicks.
When you fail a puzzle in puzzle rush, you can click on it and go to the puzzle's page, where you can see the solution without playing through the puzzle (and playing it is sometimes impossible when you've done your 5 free unrated per day as a free user, so this is appreciated). When you puzzle battle, and click on a puzzle afterwards, you don't get to see the solution without attempting it again.
Would it be possible to bring puzzle battle in line with rush here? Would be a big QoL boost for us users without unlimited puzzles per day!