You have had some useful comment already.
I noticed this in your question…
Arpeggios are not limited to just seven notes. They tend to be taught / learned as a pattern spanning across all six strings and within a distance of three to four frets. The pattern contains as many notes as are available within those parameters, not just seven.
Diatonic scales (major and the modes of major) contain seven unique notes (more correctly termed tones or pitches). And within their scale patterns across six strings and three to four frets multiple repeats will occur but we still think of there being just seven notes.
That’s a useful video to show fragments of arpeggios blended with small chunks of scale patterns give scope to make tasteful and melodic music.
Can I direct you to check out a multi-part series of topics exploring modes?
Cheers
Richard 