If you are working on a large codebase, chances are that you have a lot of modules, and your main bundle might be very big. Lazy loading most(or all) of your routes is the easiest way in angular to fix this. Split vendor chunk is not really recommended in production by the angular team in the official docs.
Table of contents
Improving Angular initial load time1. Lazy loading is your friend2. Split vendor chunk3. APP_INITIALIZER should not be very heavy4. Startup API requests parallelizing / caching5. Analyze your webpack bundle6. Use telemetry to get actual prod performanceSort: