I'm most familiar with Unity so I'll speak on that. Unity itself offers the editor (can be configured), debugger, asset manager and visualizer all in the main client. Some people have built external tools on top of Unity for things like no-code game building but the vast majority of developers directly use Unity.
I think Godot is probably the most unique of the ones you listed in that it seems like the one you might can mix and match different tools together but I'm overall much less familiar with it.
But just my interpretation here =)
I understand these engines have their own full SDK for developing with the engine, but I'm curious about the external ecosystem/integrations/libraries. It isn't a space I'm super familiar with, but I'm interested in it, not only from the standpoint of it being an interesting technology I've never played with before, but also because I'm curious if there are similar issues in the game engine SDK space as there are in the application SDK space.
Or maybe even a whole different host of issues and practices. Not sure, that's what I'm looking into.