Why aren’t swamp thing doom patrol and titans on the same earth

I’m very confused on why doom patrol are in the titans show but on the cw they were shown on different earths

The showrunners of DP wanted to do their own thing, unbeholden to Titans.

And that means we get a Cyborg without a lil’ mustache!

It gives the writers more room to create different events without any repercussions towards the other shows. And it leaves the possibility of them finding each other out on other earths open.