I purchased the 128GB one, but I play games and Apple Arcade on it, and the storage fills up quick.
Actually, I started seeing out of storage messages on my 64GB ATVs even before Apple Arcade even existed, now I have to delete something or a few somethings to download something new.
But, if you just do streaming, and have no interest in the non-streaming features, the ATV4K2 might be fine for you. Even the ATV4K1 is fine for streaming, and the older A10X in the ATV4K1 is even better than the ATV4K2 for gaming.