Variety of new cards for a novice

Hi, I've come back after not playing for about a year, I've about 150 matches back then, and up to around 30 now. I used to run a green growth deck, and now run a red pawpatrol one (only have sun goddess ammy legendary, and just got Yukimura and had axel from before).

I've gotten a lot of crystals because of the specials and having some left over from before, and was wondering what's the best way to use them?

I have enough souls for a legendary (maybe Ken), and enough crystal for maybe 20 packs.

Should I buy more Amaterasu packs to try and get sun goddess, or should I buy Halloween packs to get a variety of cards I don't have yet, and just use souls and save for other cards for my current deck?