Play at the speed you like. You mostly need to accumulate experience with many games, reading power and using shapes and tactics. Working on your fondamentals like use of the edges, cut and connect, use of influence… That doesn’t need very large time settings, it’s not about some intellectual performance but that’s not very well working in blitz either. It’s good to not play instinctively but instead asking yourself if you have to answer and where is the biggest place to play at each of your move.