I've been playing ddkk for almost 2 years now so I guess I'm qualified to give my feedback and suggestions for anyone who is starting out as ddkk/kkdd.
If you've not been playing very long:Try to switch to kddk. Commit yourself to learning. There isn't much difference between ddkk and kddk at lower levels. It's harder to learn at the beginning, but if you are able to learn it then you'll have an easier time adjusting to harder maps later on.
If you've been playing ddkk for a while and can't switch:Play maps that challenge you. Play maps with difficult but playable patterns. Have fun with some deathstream maps. Don't torture yourself by trying to FC long 200bpm monocolor 1/6 streams. You can always get better as long as you have the right mindset and enjoy playing.
For me, the learning curve going back to learning kddk was way too difficult, and I didn't enjoy struggling to FC 3-4* when I can pass 6-7* Oni as ddkk. There was a time when I could barely pass 5* maps and now I can read almost any kind of pattern. Even though ddkk is a more difficult playstyle at higher levels and it's harder to make quick improvements, you can definitely improve if you just keep playing more.
In terms of reading ddkk, I look at patterns by the number of consecutive monocolor notes in a row. Because of this, I have some difficulties with longer monocolor patterns such as kdddddk, ddkkkkk, and anything in 1/3 with more than 3 notes of the same color. When I get more used to a map I can judge a pattern's length by knowing which finger to end the pattern on.
When I try to play kddk I have a hard time with reading though, because in my opinion the reading style for streams with kddk is completely different than ddkk. Assuming you play full alternating streams (I use 2 index fingers as kddk), you either have muscle memory for the pattern, or you split every pattern into groups of 2 or 4 notes and kind of read every other note to know which key to press on each hand. Now I'm no kddk expert but I feel like the major change in reading is the main reason switching to kddk from ddkk is so difficult for a lot of people.
So yeah, kddk is the superior playstyle, there's no question there. It feels more natural for me to play ddkk because I'm more used to it, and while it definitely has its limitations, you shouldn't force yourself to switch unless you're pretty early on in your playing career. I personally want to see how far I can climb as a ddkk player. Unless you have serious aspirations to reach #1 (even top 50 would be a challenge), just play whatever's comfortable for you, and keep enjoying the game, and you'll improve.