About the chest unlock system:
There are lots of possibilities regarding a healthy unlocking system, all of them have pros and cons.
After you progress a little, you will find out that it's better for the player to actively choose what chest to open and when, depending on the time you have available for play.
Some of the implementations that create a better player experience also create vulnerabilities for the project so we have to be careful when addressing important (economy) issues, but we will think about methods for streaming up the process.
Chests have different opening times. On your 1st few levels you will get 15minutes, 30minutes chests ... but later you will get 1h, 4h ,8h and 12h chests (with different loot and, of course, chances of getting them). Also , keep in mind that the progress is getting slower as you advance and later you will find playing PvP more rewarding(talking about the number of received chests) then playing the sagamap.