I'd rather to choose to sell btc to stablecoin like usdt, much safer and low risk of low fluctuation.
But you are never going to make money that way, if you want to do that then just keep your fiat and be happy with it, if you are going to invest in this market then you need to select between bitcoin or some altcoins, if you are going to choose to invest in stable coins only do that when you are completely sure the price of all the market is going down as it did in 2018, that is the only moment in which you are justified to invest in those coins.
You can also do that if you are more familiar with scalping. Since bitcoin is moving wildly and fluctuations are unavoidable trade your BTC when the value is high then buyback when the value is low. It's difficult but still possible to process and you can attained benefits when you make it into a good timing. Every traders have their own ways and understanding whether alts or USDT if you know how then its profitable for you to process.