That was a bit of a grind. I had to give up once the game started throwing 50 ships at a time at you, each attacking for 1/3 of my crystals
Yes, via LOTS of grinding. Like I'm still feeling wrist pain from it a week later. It's worth it, though!
What I would recommend is that they don't touch crystals (and maybe very few chips, SUPER rarely). It might make it too easy, but it would also reduce frustration.
It's such a fun game and destroyed me for similar games in the genre, I noticed.