There is no best return but lowest risks. If you want the best return then you have to take the risk higher. The only low risk that I can suggest to you is to lend that to trusted people here on forum but it's up to you on how you will make your own rule of lending. You can also trade with that amount just buy those good alts.
Lending is very risky, and i do not think higher ranked in this forum would need a loan. I think much better to do is trading you can lessen the risk if you trade only in trusted altcoin and also you need to have enough knowledge in this method.
And i recommend to avoid gambling this method is not good for users who only want is to earn with small capital this method is for rich people and they only want is entertainment or enjoyment.
Yes lending is very risky that's why you are just going to lend your bitcoin to those people that are trusted here in the forum. Just make sure that you know who are those people. Because there are some that are also imitating the names of the trusted people here for the hope that they can try to scam someone with that type of borrowing.
It's always risky to give a loan. And those people whom you trust too. They may have unforeseen circumstances. It is better to come up with another way of investing - maybe in stocks or other securities
Currently just investing bitcoins is not good option if you can keep for sometime its also very good option because price is roaring and if you can keep eye on this then you can take some good profit but you must read analysis about this and need to have some good eye on price also
My mind has made the same analysis as you did, buying bitcoins with fiat for a short term, or daily trading is not such a good option right now.
The price is simply too high if we consider the history of BTC, it is over 1300$ which seems for me that it is even overvalued lately.
The infrastructure of the network is still not ready for the prices above 1200$ (that is only my opinion), because as we can see sometimes we have spam-attack, and the whole blockchain is literally stuck.
We cannot see so many unconfirmed transactions during big traffic, it is just too harmful for bitcoin and BTC users. Without solution, price cannot really get increased constantly, unless something different is going to happen.