I think, It would be great to receive rewards for the total base hero rating once in a period of time (week/month)

For example, to get 5-star crystal for a rating from 600 000 to 800 000.
And to get 6-star crystal for a rating from 1 500 000 to 2 000 000
The higher the rating, the better the reward once in a period of time
That can increase the motivation of players and give them a greater sense of the result of their progress in the game