Equivalent to Snapdragon 888. There are two versions of the Samsung s21ultra processor, one is the Samsung exynos2100 and one is the Qualcomm Snapdragon 888.
On paper, the exynos2100 and Qualcomm 888cpu parts are basically the same, with 1 super core x1, 3 large core a78, 4 small core a55, and three cluster architecture. The gpu part is the Mali-G78 MP14. Not nearly as good as the Kirin 9000's malig78mp24. Not as good as 888's Adreno 660.
In practical applications, 2100 power control, like 888, is far from ideal.
Snapdragon 888. The Samsung s21ultra is powered by the Qualcomm Snapdragon 888 processor, which is Qualcomm's top-of-the-line processor configuration.