From what I can see it appears like 5.0 is either really close to locking down its features for launch or already at that point. The main branch has things that will not be ready in time for a 5.0 launch and those modules are not present in the 5.0 branch. It’s just not ready for the point where Epic can hand on heart say that it is ready for production.
Building the engine is very storage intensive, my ue5 main folder is around 280gb. Also, if you do it, make sure you get vs2022 if you are building on windows and .net sdk 6 or one of the projects won’t build.