Seeking community input for project ideas to learn problem-solving and best practices

I recently completed 2 solo projects, a basic notes taking app and a basic e-commerce portal, without relying on tutorials. My current focus is on advancing skills in EF Core and microservices architecture using Kafka. My goal is to master the .NET + React stack and then secure full stack job opportunities similar to those attached. In my previous role as an asp.net full stack developer for a SaaS enterprise, I mainly handled bug fixing and performance optimizations. However, I encountered challenges when building features such as microservices, background jobs, and securely integrating APIs into custom client apps. Occasionally, urgently needed features were reassigned if I took more time than planned to develop them. I'm seeking community input for project ideas to improve project planning (estimating time required to complete tasks) and problem-solving skills for efficiently architecting features to minimize "client found bugs". Let's collaborate and grow together in our development journey!