Poor Audio Quality of Sampler

[iplanwebsites]

Even with quality samples, my Sampler audio quality on MacOs is very poor.
Am I missing something, or it's just inherent to the pitchifting algorithms available the browser?
I wouldn't mind pre-processing the samples if it can improve quality.
I haven't found other alternatives here so I'm really wondering how others are doing it.

[iplanwebsites]

For reference, here's a UI where you can test Playback of different sampler setups.
https://app.aura.town/