Which holiday crystal is best for me??

Hàrshx23

Well it's my 5* and 6* roster I lack a game changing tech skill and cosmic( can't rank cap marvel as no materials)
Which crystal should I open.
I will complete legendary quest in few hours and I'm in dilemma
Should I try for cosmic ghost Rider or for 2k19 ones or for ghost or corvus crystals

Hàrshx23