Add a limit to the number of trophies someone can lose or take from the same player. Could be hourly, like the one we have to attack someone more than 3 times.
So, on first raid, if I succeed (or fail), I would gain (or lose) the normal amount of trophies, let’s say 10. And on second and third raids on same player I could only gain (or lose) 1 trophy.
Plus, you also need to lower the number of trophies someone can take or lose in raids out of matchmaker, I believe the current one is 15, that’s too much.