It’s above your pay grade. If I were you, I’d reach out privately and suggest that the customer seek a competitor’s product that has the features that want, and tell them that there is no desire within the company to support free software or self hosting.
I would say service-oriented is definitely but sometimes microservices are more trouble than they’re worth. They scale well but can be overengineering for smaller scale applications. And like Donald Knuth says: “premature optimization is cringe”