If you just want to invest in one coin for long term holding , I can't help you figure out the crypto for you .That's not a easy task for us.
I suggest you invest your 5K into 3-5 icos to earn 50K at first , then plan to earn more .
it is true that you say that by having 5k capital if my advice is better invested in the 3-5 ICOS in order to get a pretty good profit but with a long reach if you want to get a great interest