Hello!

In my opinion, it is best to get other Element cards first before getting the Stats/Debuff cards (if you are using different teams that has different P1s). Like what I did to mine, I started maxing my Temari card since Assist Cards came out during the days where Jonin Minato was still on the top metas, followed by maxing my Gaara card and Mei card (For my Kushina and Tenten teams) and then Onoki card when I completed breaking my Kakuzu. Tenten is a good choice also too but having other Element cards ready is much better. Minato card is also a good option especially if you are fighting someone with close initiative count where using Minato card can overcome the gap and gave you an advantage.