Right. It is all about the time you put in.

But one thing I like to stress is: You get to decide how to spend that time. Sure it is occasionally good to spend the time on "no fun" practise, especially if you feel your playing is lacking. But you don't get magically better results if you suffer while practising.

I'd argue the opposite: The person who has fun while practising will also learn and they will be inclined to put more hours in.