Thank you for your question!
The normal rate for 4✰ cards is 0.018%. For new cards, that rate rises to 0.400% on the normal event gacha and 0.044% on the rate up gacha.

On normal gachas, the 2✰ rate is 1.883% and the 3✰ rate is 0.198%. On the rate up gacha, only cards that match the event type or characters are available, and these rates increase to 5.206% and 0.607% respectively.

All 4✰ cards can be pulled from a rate up gacha, but event and character boost matching cards will be 0.044% along with the three new cards, while others will be 0.022%.

So, if you just need new cards for the event, the event boost gacha is definitely worth it! If you’re looking for the new cards though, you’re better off with the normal gacha. Hope this helped!