How long after being denied for a credit card should I wait to apply again?

Don't panic. Credit card companies get very basic information about your credit and flood you with advertisements because studies show that people tend to get attached to their "first" card and hold on to it longer than any other. So everyone wants to be first in the door.

Be patient. You don't need a credit card for anything, despite what the marketers and "nerds" tell you. Yes it offers conveniences, most of which you can get from debit cards as well, and some modest rewards, but it's not something you need to move heaven and earth to get. Get a bank account, put your income there, and use a debit card so that you don't outspend your income.

Your credit score is good mostly because you haven't messed it up yet. It's not a status symbol; it's just a sign that you have been reported to pay your bills on time.

You'll have better chances of getting a card once you have income to prove that you can continue to pay bills going forward. There's not any compelling reason to rush and get a secured card or one that has fees of any kind. After you have some stable income history banks will continue to fawn over you if they think that you will get one of their cards. Their hope, of course, is that you'll overspend (like many people do), roll over your balance for a while, and pay them a lot in interest and fees. So long as you DON'T do that, your credit score will stay high and they'll keep coming after you.

You will have to talk to the credit card companies regarding why they denied you, especially Discover for the secured card.

The things that jump out are the lack of income: "I got a job a month ago" followed by "My employment started on 7th December 2020". That means that you have worked for a little over a week. You also mention you haven't even received your first paycheck.

Even Capital one may see you as a new customer, because your bank accounts have only existed for about two months.

You have a good score, but as you mention the fact that you have trouble getting your credit report because you have only been in the country a little more than a year. The credit card companies only see part of your file when they do a soft-pull, the rest of the information either comes from you in the application, or via the hard pull when you apply. That is the moment when applications triggered from advertising, or mail solicitation are rejected. The score looked good but the details wee found lacking.

Over time you score will improve, but more importantly the file will become thicker.

Wait a few months and go back to your bank and talk to a person before applying for a secured card.