I would say just holding, the safest way, as far as I know. If the btc price rise you will win, of course, but unfortunately there is no warranty that this actually will happen.
I do not think you will get a fixed income of only hold bitcoin, you do not know when you're going to sell your bitcoin, so you do not know when you're going to get profit right ?
Exactly, holding will allow you to make profits only if price goes higher in future and that also be one time profits only when you sell them and then again you need to buy them and follow the same process again and again and that can be time consuming.