First credit card, NISA, phone plan?

Hello! I am a Japanese citizen planning to move back to Tokyo next year after college and wanted to know what the current best options are for mainly credit card and phone, or also a NISA. I currently only have a JP Post bank account and will be expanding once I move.

I see Rakuten is often named for a good card/NISA. Is it beneficial for me to try to get Rakuten Mobile + card + NISA in the same ecosystem, or are there better options out there? Thank you!

by OsakaMilkTea