But I agree that there's not enough demand for services like this. As you said, it's easier for users to deposit their money to some DeFi business and get their interest rates rather than finding people directly on forums and creating contracts with them.
I don't know what percentage other than bitcoin that most lenders here accepting and what kind of problem they encounter, but have you tried to ask them in regard to your product? It would be the best idea to directly ask them to get a better concept of whether they all really need it or not.
I think even if they all thought your platform might be has some utility, it is still a niche, the lenders/borrowers on here. So yea, the scale of usage won't be enormous, I don't know which else of the market specifically need this kind of solution. And it is also limited to a specific blockchain.