performance by the musicians itself is not as central to the composition
Extremely debatable. With Renaissance and Romanticism came the cult of personality around celebrities. Lisztomania basically mirrored Beatlemania but for the virtuoso Hungarian pianist and composer, in the mid 1800s. Haydn and Paganini reportedly had a rather large female followings who weren’t really interested in their knack for musical harmony. IIRC, there are accounts of Mozart indulging in the lifestyle of a young royal composer with some renown.
I don’t know if he’d be making electronic music, honestly. Mozart broke so many of his contemporary musical rules, with all that has been invented since, I find it hard to believe he’d limit himself to it. Maybe progressive/experimental stuff ala Aphex Twin lol?