C# remains a plus for a lot of game code, but not as much as you might imagine. C++ usage in Unreal is really a small restricted subset of C++. For typical gameplay code, you play within their rules for uclasses/ustructs/etc and it feels pretty much like any other managed GC language. Meanwhile, for places where it matters, "raw" C++ is of course always available.
Re: iteration time, Live++ [1] integration has matured a lot in UE5. That means compiling most code changes without having to restart the editor (or even in-editor game session). Again, not much different than Unity here, though both can break and require editor restarts for certain types of changes.
To double-down on OP, by far the biggest advantage Unreal has for professional development (aka anything you want to ship) is full source code. I've worked in both but can't imagine going back to a black-box engine. Unity/Unreal are both MASSIVE codebases ported across every modern platform imaginable and guess what: there a plenty of bugs in both. I can't imagine going back to an engine where I can't A) see what it is doing and B) fix issues without waiting weeks/months for a patch.
Re: iteration time, Live++ [1] integration has matured a lot in UE5. That means compiling most code changes without having to restart the editor (or even in-editor game session). Again, not much different than Unity here, though both can break and require editor restarts for certain types of changes.
To double-down on OP, by far the biggest advantage Unreal has for professional development (aka anything you want to ship) is full source code. I've worked in both but can't imagine going back to a black-box engine. Unity/Unreal are both MASSIVE codebases ported across every modern platform imaginable and guess what: there a plenty of bugs in both. I can't imagine going back to an engine where I can't A) see what it is doing and B) fix issues without waiting weeks/months for a patch.
[1] https://liveplusplus.tech/