In the current state, how can you get cards to level 14, let alone 15?

I’ve recently come back to CR and noticed that it feels impossible to get enough cards to level up to 14. No season shop for wild cards or books and other sources rarely ever give Wild cards. Whenever I want to level up a card to 14, I better be damn sure that’s the cards I want to upgrade, or else it’s going to be another month at minimum before I can do it again. Even the $12 diamond pass has horrible value if you really want to upgrade cards. What am I going to do with 4 legendary wild shards?

With level 15 cards being already super inaccessible, it feels ridiculous for level 14 cards to be this hard to obtain. It sucks knowing that I am pretty much locked into one deck if I want to actually win games. Even if I spent some money it seems like there’s no value anyways. I want to know if anyone feels similarly because something needs to change about this.