You are looking for an analog logic module! Mystic circuits Ana is my top recommendation.
-- Miszczyk
Save that that's not exactly a "logic" module...it has some very useful functions, however, including multiplication of CV levels. But "logic" for the most part refers to the actual Boolean gates themselves, while this is more akin to an adder/4-quadrant multiplier/discriminator. Definitely does more than the SumDif, but the question then becomes whether or not the OP can fit that into their build by freeing up 4 hp somewhere.
Maybe MG needs another category for "CV Arithmetics"...? It's not exactly "modulation", because these recalculate the CV level instead of imposing a modulation curve on them. And it's not "logic" since there's no status-dependent digital on/off states. Nor is this a "comparator" as such...hm...