Thanks for the reply. However I tried that a week ago when I first realised nvidia settings didnt work for me.
It didnt work either, for some reason. According to my research, it didnt for many people(for various programs, not just blizzardbrowser.exe)
Edit: For the record, what I did was this, but for the correct blizzardbrowser.exe thats in Warcraft III>retail>x86_64>blizzardbrowser>blizzardbrowser.exe: https://www.howtogeek.com/351522/how-to-choose-which-gpu-a-game-uses-on-windows-10/