I started with Sibelius in the late 1990s, on an Acorn RiscPC, and stuck with it through to late 2016 (though I do nip back in occasionally to do quick edits or revisions of old scores).
“Intuitive” is a term that seems to come round again and again, and it’s one that I have trouble with. Dorico is not a simple iPhone app. It’s not possible to figure out how all the functionality works in an afternoon. It’s professional software with an extremely broad feature set, and software of this variety is always going to take acclimatisation time. On the other hand, it’s laid out in a consistent fashion, so once you’ve got to grips with where things are likely to be it’s not difficult.
I think it took me a couple of weeks to get generally comfortable with it, though of course at v1.0 there was less to learn. As a working whatever I am (engraver? arranger? copyist? pianist?) Dorico feels like a much more comfortable creative workspace than Sibelius ever did, and the printed output requires much less tweaking in order to look balanced on the page.
The switch will go easier if you can leave everything Sibelius has taught you at the door, and go back to thinking semantically. For instance, if you’re looking for a Line, what kind of a line? If it’s an ottava Line then it’s in the Clefs and Octave Lines panel; if it’s a Pedal marking then it’s in the Playing Techniques section; if it’s a first time bar then it’s in the Bars and Barlines panel. Why? So that Dorico can automatically take the notes up or down an octave, or give you a semantically appropriate Pedal line that can acquire retakes wherever you want them, or automatically give you a repeat barline and a second time bar.
Good luck, and welcome to the forum.