If I was the dev team head, could have argued to keep the golden upgrade kit in the premium pass with key master upgrade kit only and replace golden upgrade kit in the non-premium event progress timeline with fragments of keymaster workshop and made the board with 1/1/1/1 (with heavy heart since heart expects 1/2/3/4) but chest category to be handled with max of 6 keys, no 9 keys on any chest.
my classification of chest is very simple,
bronze chest two variants, one is 6 keys and second one is 3keys and 3 keys of two gems (randomly)
silver chest two variant, one is 6 keys 6 keys(two gems), second one is 3k 3k 6k(three gems)
gold chest two variant, one is 3k 6k 6k(18atom) second one is 6k 6k 6k(23atom)
so the concept I could have made is, whoever reaches 5500 with premium pass, gets golden upgrade kit and in non-premium pass fragments for one key master level1 will be fully achieved and also two upgrade kits of key master obtained through premium pass by reaching 5500. These will not create any imbalance and keep the fun in the game too.
@Juber, kindly request the dev's to rethink on the balance applied.
There are better alternatives available and still not making the change is somewhat hurting.
Give some happy news, current one is nowhere nearer to have any fun to call as a "celebration event"!!