Sometimes I also use DCA for buying 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 every 10% of it 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.
DCA means you accumulate one asset with time, gradually and according to your plan. When you practice DCA, price is not a big matter with you. Because you do this plan for long term investment.
I mean if you plan to DCA with $100 every month. You can do it every month and don't care of how a price in that month is. However, if price has deep correction, you can spend more than $100 as plan to accumulate more. So you can spend $200 in a bearish month if discount is big in your opinion.
https://dcabtc.com/