Ref: themes-2024/src/theme-style-variations/render.php?marks=23

Here a string uses "Style variations (%s)" as a plural-aware string ( _n() )

When the count is provided in this way, this should be just a normal string.
_n() would be the choice if you were to say "%d style variation"//"%d style varitions" instead.

Also, if you use %d rather than %s, then it's easier for a translator to see that this is a number (and not, for instance, the name of some style variation.)