I dislike internal hysteresis and will do almost anything
else to get hysteresis in the larger assembly.
I believe you're best off creating a perfect front end
and then figuring out to get hysteretic action at the
end. Superposition, like, after getting the fundamental
function sorted.
Cross-coupled loads on a continuous-time comparator
are one place to fiddle, going over 1:1 will put you hysteretic.
But this can be hard to control, the magnitude, while an
external switched-resistor network feature in the feedback
path (a PMIC always has one of those) is pretty corners-
consistent.