Is this the best way to notate this type of thing, or is there a better way?
The exact notation depends on the specifics of how you'd like the arpeggio to be executed. Here are a few possibilities. (The open-ended ties in the first example can be used on any of the others to express sustaining the notes.)
As notated, it's an arpeggio played in time. A harpist would interpret the notation literally.
Allowing that all of the notes should be sustained, open-ended ties will communicate that.
A more concise notation would write the arpeggio as a chord and include the arpeggiation symbol alongside.
As grace notes
Allowing the topmost note is the "arrival" note, it could be written as grace notes (which are given no time) leading to the main note (which receives the notated duration).
In this case, the arpeggio would be interpreted as being played out of time, according to the interpretation of the performer.