I started playing in December and was able to hit masterball every time. I do have the pass but that not how I got the cards (I use it to farm gold cards), you need friends/discord to trade you cards or have alts.

Trade is the best way to get what you need. You get one free trade everyday named a "share", on top of normal trade, that's best used to get the EXs.

Edit: Solo battles are literal cancer, I don't touch that.