Anyone Familiar with Loan Business?

Hello all, I am working on a platform to provide loans in a super niched market. My users are mostly business owners who themselves have their own customers. We are providing an installment payment method for their customers if they cannot pay full at once, but may be willing to pay a small portion for each month, say 3 months, and 6 months.

I've contacted SynapseFi which has this lending product to use, the product sounds perfect and may product us all-in-one solution for lending. If I use SynapseFi, I don't need to deal with any license and compliant issues, which is good. But problem is the monthly fee is over$20k, far above my budget for my garage-based side project. I will soon burn out all my cash if there is no VC money.

Actually all I need is to send money to business owner's account, and collect monthly payment from their customer via ACH.So I am also thinking to directly lend my own money to their customer and collect their monthly payment via ACH back to my account. But I am not sure if by doing this, it will cause some legal issue.

If you guys know any alternative to SnaypseFi or any affordable legal ways to do so, please kindly advise. Thanks & happly holidays!!!