I’m a noob like you and I agree the focus rewards are mission impossible to start with. I did much better when I ignored them. Try to League up to Bronze II and the more winning streaks you get & game points you get the better the rewards. Right now I’m getting 16 to 60 FP & SP per win and I’ve already won 6 Season’s chests with 6 days to go. It took we 5 days to win 2 and now I won 4 in the last 2 days. I make sure to own at least one or two cards per battle.
It’s definitely harder than it was though! Good luck!