I am in the same boat. I had to file in 2018 but did not have to file for 2019 but I did anyway. Did not get a refund or owe on 2018 or 2019, so no direct deposit info on either one.
I have SSI and VA Disability direct deposited every month. When I went to the IRS site, it said I qualified but they did not have enough info for direct deposit so go to next page and fill out tax/bank account info. I tried to enter the info, even though I should not have to, it kept giving me website errors, and after a few attempts, locked me out for 24 hours.
If the systems are talking to each other, they should have enough info to direct deposit the payment, without this extra step.
In your and my case, might be better to wait until the day of your regular deposit schedule from SS. From what Mnuchin is saying we should get both SS & stimulus money st the same time.