I have recorded a live guitar part. But some notes are slightly off. So I tried to correct that in Variaudio but when I do that with guitars they start sounding weird, laggy, or like if the audio got stretched wrong.
If I hear that correctly, the notes are overlapping (polyphonic).
Variaudio is meant to work with monophonic audio, such as Vocals, flutes, bass, lead guitars and violins mostly, etc. Basically everything where you don’t hear or play two notes at the same time.
There are tools out there, which can tune polyphonic audio, such as melodyne, Variaudio (unfortunately) can not.
To explain, why this sounds weird is:
Vari audio most probably shows the highest note, but when tuning, you tune the entire performance, so while you may tune the higher note, so it is perfectly in tune, the lower note which still rings from before, gets detuned. So if you straighten the pitch, you may introduce a vibrato on the ringing note.