When adding fields to classes, you don’t need to relaunch the engine.
Pressing the “Build” button will rebuild, and re-load your DLL, and have the new class available.
(This is without “hot reload” – just using the regular button-based build-reload.)
After doing that 100 times or so, you may run out of DLL handles or something, and need to re-launch the editor. It will clean up unused re-build DLLs when it re-starts, and sometimes there’s an impressive number of them!
In general, I don’t use “hot” reload because it wouldn’t give me anything I would need. Once I know what I want to do, there’s code to write, and somehow staying in the middle of game state, and then reloading my updated code into this old game state, never really felt all that compelling to me. I guess that’s my “secret” 