Re: apex stuttering
If you stutter before playing the game at the loading screen, in lobby, when changing game modes or even in game where effects are being shown to you, that's because the game doesn't compile all shaders before entering it. A full shader compilation takes more than 2-5 minutes, reaching one hour for some games.
You need to wait and compile all shaders in lobby by changing game modes, looking at the battlepass, store, etc., to not have any stutter.
Keep in mind that DX12 is in beta so expect a lot of bugs from it.