It doesn't take place on the same Earth as the other shows, but that's kind of geek hairsplitting. Same actors, same producers, same network, essentially a continuation of the same DC production engine that generated all the other series. Even saying it was on a different Earth was something that didn't come up till the second season finale. Before that, the producers talked about it as part of the Arrowverse, and crossovers were even planned before COVID nixed them.