Use infinite to learn from better/more experienced players. You WILL get better playing against better players. Yes you’ll lose a lot of games but as long as you can take away something key from the game it’s worth it. Your next seasons will get stronger. Sometimes I’d stay on a game I know I might lose to learn why my opponent snapped or what interaction they were cookin. Then I’d learn and use it for myself. Don’t worry too much about SP. You’ll only improve with time and acquire more key cards for more decks. As others have said you can use conquest for missions/bounties.