There's a running joke on my Discord server, that the answer to most #UnrealEngine questions is "did you see how Lyra handles this?" because the Lyra project is so completely full of good examples. UI, multiplayer, editor tools it's all there.
https://www.unrealengine.com/marketplace/en-US/product/lyra
Lyra Starter Game in UE Game Samples - UE Marketplace

Lyra Starter Game is a sample gameplay project built alongside UE5 development to serve as an excellent starting point for creating new games. We plan to continue to upgrade it with future releases to demonstrate our latest best practices.

Unreal Engine
@_benui I find the whole Gameplay Plugins thing that Lyra does deeply confusing.
For the most part the way that Unreal wants projects organized is the way I want to organize them, but the level of compartmentalization of that system is too much.

@DKesserich @_benui it's definitely harder to get into than previous samples, but I'm glad that we finally have a sample from Epic that shows a more complex architecture than the previous ones, which usually failed to address how to integrate the various engine features at a larger scale.

That being said, you can still build games without modular gameplay and many projects will be simpler and better for it