the best investment you can do is to save some money and buy some property. decision making always have a risk. but if you invest in somethings where you can call it as an non current assets it could be useful in future. and one more thing if you want to grow your btc with less risk is impossible but you can search up what gambling site is trustable where you can invest your money to double it up.
No gambling site can double up any investment, that is a wrong concept, though some people can win in gambling (if you are talking about that) but that does not always happen, so it is better to invest the money somewhere else where it is not always dependent on luck.