Here's a Scoring Notes article about a new feature in Sibelius, allowing the creation of parts from a single score staff with two parts.
https://www.scoringnotes.com/reviews/sibelius-2025-2/
It's interesting that they've taken the opposite approach to Dorico, which condenses the score staves, rather than splitting a single one to make separate staves.
But I'm surprised that it didn't have this feature before ... 2023...?
Finale had the ability to make parts from individual Layers, though there were many limitations; some of which were fixed in 27.4, ironically.
Sibelius introduces "de-condensing"
Re: Sibelius introduces "de-condensing"
In theory there was a plug-in, something like... "Split staves into parts" or similar.
Nothing built-in, though.
Nothing built-in, though.