Do I need to choose stock over crypto?
You can have both, no need to chosoe one over the other.
I don't want my attention to be divided.
There is very little thing to do if you buy bitcoin only and ignore altcoins, especially if you opt for DCA investing strategy which is by far the most newbie friendly. Once you set DCA plan, all you have to do is learn how to properly and safely store your bitcoin and you are good to go.