Getting clients for the software company

We are planning to start a software service-based company as a startup. Initially, we tried acquiring clients through freelancing platforms such as Fiverr and Upwork. While we managed to secure two clients and successfully completed their projects, we have struggled to find long-term clients for our startup. Clients on freelancing platforms often have a short-term vision and tend to seek low-budget services. How can we attract premium, long-term clients for our business? What strategies would you recommend for our company, and do you have any suggestions or advice? Our portfolio: Atomycoders (Google it)