As others have pointed out, flows are one of the main principles of Dorico. You can use just one flow (uncheck Project will use multiple flows when you first create a project); you can suppress flow headings (Show flow headings: Never* in Layout Options); but there is always a flow under the hood, because that is how Dorico organizes the music. And that’s one of the things that makes Dorico more powerful than other notation editors. To paraphrase Daniel Spreadbury, who moved from the Sibelius team to the Dorico team, it’s more intelligent this way—and there’s nothing artificial about it!
Believe me, I have plenty of Sibelius nostalgia myself—but flows were one of the things I welcomed in Dorico right away. Under the old modus operandi, if you did want another movement/number/piece, you had to manually enter a system or page break** and adjust the options relating to said break. But it was all still one giant “flow” under the hood, even if the other programs never used that term. Plus, settings like time signature and key signature were retained from before the break, whereas flows in Dorico reset them. I can only assume that Finale was similar in these respects. I sometimes work with single pieces of music as well, of course, but since the newer versions of Dorico make it easier to hide flow headings, I’ve never had a problem.
*Only affects completely blank projects, not templates, as mentioned above.
**Speaking of systems and pages, Dorico also offers frames, which are very flexible and useful in their own way.