When I played it, the metagame seemed to be evolving towards using time-traveling either for cheesy mates (queens are OP), or as a "no u" mechanic to deny your opponent their good position. Which I think is a shame, the concept I think would work best if time-traveling was rewarded when used proactively and trying to set up plays.
I think the first thing I'd patch into it would be limiting the maximum time or board movement. That way your opponent can't deny you your good board by jumping 30 turns to the past, well maybe a few turns back yes, but it's too frustrating to build up to a good position and not being able to use it for dozens of turns until you've caught up, if you ever do. It might also make queens a little less OP since their potential mates are more limited, they can no longer randomly mate a king 12 boards in the past, but they can still be extremely threatening in the past few boards. Since the game's mechanics are heavily inspired by classic chess I would propose 7 time and/or dimension moves, since that's the farthest a piece can travel on a classic board.