Film music is generally (no rules without exception, obviously) by its very nature not very “virtuosic”, as that type of (solo or multi) instrumental writing tends to be a showcase, a “wow!” flash, very expressive, that demonstrates the superb mastery of an instrument and by its very nature so draws attention to itself, something that film music is (usually) not supposed to do.
I have a lot of solo instrumental music, and love Beethoven’s Piano Sonatas, or many other solo piano works, but I can’t think of a lot of solo passages in film scores. However, John Williams has at times beautifully integrated the piano into his scoring, like for example MONSIGNOR, which is why I always hoped he’d write a piano concerto one day.