after reading the comments, I set up the Federal Bank app using my FI account. Jupiter account details didn't work for sign-up, strange.
But after set up, it shows both Jupiter and FI account details. So I went to the credit card option, which said to apply for one, redirected me to the website, and asked for Mobile number verification and later my PAN number. It showed all 3 variants, Signet with 3 Lakh, Imperio with 6 Lakh, and Celesta with a 10 Lakh limit. I chose Celesta, which was approved instantly, and a digital card was generated in a few moments. It didn't ask for VKYC or a photo.