Yea a powerful 6 core will always be better than a weak 8 core. I do think that if you can afford it, it's better to get a strong 8 core than a 6 core but most people won't need it. If it's a case where you have to choose between a 6 core + powerful GPU or 8 core + weaker GPU, it's always better to get the 6 core + powerful GPU.
PC Specs: CPU: 7800X3D || GPU: Strix 4090 || RAM: 32GB DDR5 6000 || Main SSD: WD 2TB SN850