how does arcane relate to lol at all

if so many characters died in arcane (ambessa, jayce, viktor, jinx, heimerdinger and warwick) and arcane is canon, how come are they still alive in the game?

I know it seems king of stupid but this doesnt make sense to me at all, as all league characters are supposed to still be alive in the present day. also, why does caitlyn have an eyepatch if she doesnt have it in game?