The latest exynos chip replaced Samsung's custom CPU designs with stock ARM ones, presumably because exynos variants of the S20 lagged far behind the snapdragon variants in performance and battery life.
This could be temporary thing, even qualcomm has done it in past but gone back to own designs after 1-2 generations.
My guess is that they needed the engineers for AMD GPU integration and ARM happened to have a good design at that time so the choice was simple.
I think the original comment was referring to the initial backlash Samsung received after putting inferior Exynos Chips into non-US devices, that were significantly less performant while drawing more power than the devices with the Qualcomm counterpart.