Japanese credit card help/advice

I just applied for a Rakuten card and was rejected. Maybe I jumped the gun on trying to get one so fast as I've only been here for a month but only using cash is EXTREMELY tedious. My bank will not allow foreigners to get a credit card through them so I went with Rakuten. I'd prefer to get a card through them as they also have ETC card that I would love to get as well.

After the rejection email I called them and asked what the deal was and what I should do differently but they are not allowed to disclose why I was rejected (which for the life of me I DO NOT UNDERSTAND WHY). I had read on another post that they had kinda done the same (although with a different card company) and he kept pressing why he as not accepted and they told them to reapply and then they were accepted in 10 minutes. The lady that I had spoken to didn't say much and I asked a couple of questions that she did not answer and just told me to reapply, but I'm nervous to reapply and get rejected again. I heard that if you get rejected you should wait a little while to apply again but I just don't know how long I really want to go without being able to just buy the things I need at the store without having to have cash on me at all times. Is it a bad idea to reapply again so soon? Any suggestions on what I should look out for when applying? Legit any advice would be super helpful.

by Few-Cartographer220