Spotify's collection of recorded classical music is vast, with many of the best ever recordings of pieces on there. Some famous pieces, such as beethoven's works, have 100 different versions.

It can be worth googling the piece, to see what comes up about it, and its history, and the different interpretations.

In terms of the range of difference between what the original might have sounded like, vs a modern interpretation, you could check out the Voices of Music version of Pachelbel's Canon, vs say the Neville Marriner version. The VoM version is performed on vintage instruments, and they try to adhere to what their belief of how it would have been performed, whereas Marriner's version is the more familiar version to our ears.

This is probably at the more extreme range of variance in interpretation, as the piece is so old, and little of Pachelbel's music survived. Interpretation differences for something like Paganni's work would be more subtle.

But what's most interesting, is how different interpretations can be of a composers works while they are still alive. Recordings exist of Gershwin's Rhapsody in Blue, featuring Gershwin himself, in 1924 and 1927.

https://youtu.be/VGvuUOtHGkk

https://youtu.be/PA3ryT2HJK4

There are some quite noticeable differences in interpretation, even between these two performances.