Y'know, Mitsuki did jack in Naruto gaiden, additionally his goals weren't mentioned in the Boruto movie, in fact the Boruto movie made it clear that Boruto chose to be like Sasuke and Sarada chose to follow Naruto, no mention of Mitsuki in the parallel, in fact there was not much mention of him in the gaiden either, I guess that means Mitsuki is out of the picture right..... right, no, it means Mitsuki was the focus of the oneshot, it was his time to shine and he got it, he also got his motive, to be the moon to Boruto's metaphorical sun, the same thing Boruto mentioned he was to be to Sarada.
The Boruto manga isn't even out yet, hell Sarada's presence could be absolutely inconsequential to the manga at large, but as of now, Sarada is not as you say out of the picture. Just my 2 cents.