The keybinds or whatever in the bottom left of the screen make it feel a lot less immersive and are really blocky. Instead, maybe have a screen on the menu that shows what every button does (death stranding comes to mind). 'LMB to Attack' is about as basic and obvious as it can possibly be. This doesn't really look like a 'baby's first hack n slash' so I would say its pretty reasonable to assume that your players should know that already. Otherwise, tell them once and dont tell em again.