Are you kidding? Maybe the earlier Samsung phones, sure. But ever since the Galaxy S6, Samsung phones with Snapdragon CPUs (i.e. all the US models) have had locked bootloaders that are notoriously difficult to circumvent. Pretty much all custom ROM development on recent Galaxy's are aimed at the International Exynos-based processors for that reason. The GS8 even takes it one step further, where if the phone detects it has been rooted, it will cap the battery at 80% charge.
