Question about investments of resources

So I have 4 cognitive shards X60. Am wondering should I use them on Fox or save them for turbo. Am gonna pull a6 berry so will get very close to getting 6 X60 shards so I can a6 either one.

What’s most worth it?
If it helps I don’t have summer puppet or Akihiko (good dps for turbo)

I also have all other support (twins, chord, wind, s Marian ect)

Thanks for help