Get out of bronze. At the same time you should be at the highest tier of each league to produce enough RShares - I mean, if you are playing in Bronze, do it in Bronze 1, not Bronze 3.
Just do a little investment and buy high CollectionPower cards to rank up into Silver 1 or 2, there you will earn something in between 5/12 chests a day easily plus 0.10/0.30 SPS per win.
Remember to leave some spare DEC for rentals and Stack a few SPS so you can begin the unstaking wheel rolling.
Cheers.
RE: Season 12 / day 2 / no rewards