Sometimes I also use DCA but not at high price periods. If you already did it for 4 years then I think you can sell it anytime, just in case you are in desperate for money. But if not then I suggest you to sell at bullish market only. Just wait until October or November, maybe you can sell it at good price. Bitcoin price movement is very volatile and you can see it clearly from the chart. If I were you I will sell it every 10% at bullish market, not just based on time but also based on chart, if the graphics is fall then wait until it go up again. I hope you can get maximum profit.