Yeah, you could turn a trade into a DCA as well. Lets say that you bought something and you want to sell it as quickly as possible when it goes up, however the price suddenly went low instead of going up, that means that you are not going to end up with anything better, because it would be a loss if you sell. In this situation some people just end up buying more, to make sure that it goes well.
Assume you use DCA for Bitcoin, I agree that DCA is good for your portfolio with a big condition that you DCA with your money, not from any loan or don't use any leverages. DCA only with Spot market and your own money, then a next big step is withdraw your coin and store it in your non custodial wallet.
Don't store it on exchanges because you use exchanges to DCA in. They can freeze your accounts, their exchanges can bankrupt and many risks you can not control. Be your own bank with non custodial wallet.
I feel like that is not that bad and it looks like it would definitely be a good deal. This is of course not going to be easy, but if you keep DCA your way out of that position, it would be part of your trading strategy. That would be "sell if it goes up, dca if it goes down", which isn't really a new strategy at all.
If this practice applies with altcoins, it will be terrible. Because DCA with altcoins can make your loss bigger and bigger, then your portfolio value can drop to nearly $0.
Terra death spirals with $UST stable coin and $LUNA token is very big lesson for people who DCA with altcoins.