eggbug enjoyeri wish when you google stuff like "how does slerp work" you could find something in between "call your engine's slerp() function!" and "here is a phd level math paper"
incidentally did you know the quaternion formulation of rotations is really just axis-angle in a trenchcoat
there was never any reason to bring hyperspheres into the discussion and confuse thousands and thousands of gamedevs
it's just axis-angle and some calculations [which may be derived from the hypersphere interpretation of a 4-vector but don't worry about that]
(clarifying edit) if you're implementing an engine or math library you definitely do need to understand how quaternions work, but calling your engine api primitive "quaternion" instead of "orientation" or "rotation" or something similar is very silly and misleading to people who just want to make thing go spin