That's the end goal isn't it? I'm hoping you can reach out to TenX/PAY or similar and find a solution (with fees) to make funds in "available" accessible to a card for everyday access. There's SO many types of investing, and passive income investment is a big one. Having to juggle your passive income into an account isn't the best result... direct access is going to have SO much more appeal, and as it's a convenience thing, your fees CAN reflect that, if you choose. Quality of Life for the user, and profits for the business'.
Hope it CAN work. Cheers.
Customer support service by UserEcho