Web App portal complete Management Needed

I need assistance in managing my existing web app portal built using Next.js, along with Render, MongoDB, and hosted on Hostinger. The scope of work includes handling any minor or major rectifications while ensuring the platform remains active and functional at all times. The app currently faces issues related to performance (slow loading), functional bugs or errors, and design/user experience problems, which I would like addressed promptly.

Specifically, I need improvements in the frontend design to enhance responsiveness across mobile, tablet, and desktop devices. Additionally, there are deployment and hosting configurations that need refinement. Throughout this process, I request that the source code, including environment files, be shared with me consistently via GitHub. Please also add me as a collaborator in your GitHub workspace.

As someone from a non-tech background, it’s important to me that I’m kept updated on the progress. I require a developer who is proactive, responsive, and ensures my web app stays operational while addressing any emergencies or changes, big or small.