A new chest reward system is needed
The chest reward system needs a rework. The resources and exp it offers are completely irrelevant compared to the new battle system. The energy and time spent on chests are simply not worth it.
I opened around 40-50 chests and got 700 exp total. I can get more than that with just 3 battles on an active Diamond VIP.
The system might make sense for new players, but it becomes useless pretty quickly. The exp and resources don't need to be fixed outright, but they should scale with the account or kingdom level. They should be minimally worthwhile at every stage of the game. If I need millions of resources, getting 1x, 2x or 5x from chests makes no sense. Same goes for exp: it can't be flat across 1x, 2x and 5x multipliers.
One idea to make chests more interesting: add cards to the prize pool. Utility cards with a higher drop rate, monster cards with a lower one. If chests become the only free way to obtain them, they'll automatically become relevant again.