Good thing is you can do DCA even in other tokens not just Bitcoin. Adding research to any other token that has great potential will be a great help and to do DCA which has also risk but you do believe in the project itself is enough. Invest what you can afford to lose and wait for years to profit.
How well do you Believe that other token will do too well In the next 4 to 8 years that you might want to DCA? It's true that when you're a bit sure of the token you want to invest in, you can choose to use the DCA methord on them and truth is that if thier is a project that has the potential of doing very well in the long term as Bitcoin, thier is nothing wrong to DCA on that token but we all know that in terms of the past, present, and the expected future performance of most of these projects you're looking at, non of them has a result that's relatively comparable to Bitcoin.
Thier are somany reasons why you should DCA only with Bitcoin and one of the core one is that even though Bitcoin is still volatile and risky just Like the shitcoin you might intend investing in, Bitcoin still remains the most viable and unique digital asset that has had reasonable past data you could easily look at in terms of using it for doing future projection on what Bitcoin price will look like while buying using the DCA method. Even though Bitcoin is still a reputable asset, it's still advisable to invest what you can afford to loose, this only means that for a shitcoin, if you plan holding them for the long run, you risk losing them all before you've even reached whatever amount you intend getting to.