Hi @AyanPalit,
Thanks so much for your helpful reply and for pointing out the AVX2 requirement.
In my case, the Assistant feature was tied to the ArcGIS Pro AI Assistants Early Adopter Program. I was lucky to be directed—thanks to a suggestion from @KoryKramer —to someone at Esri who sent me an invite and the necessary installers.
After completing the setup, I now have the Assistant active in ArcGIS Pro.
Appreciate your support!
Best,
Muhammad Elbagoury