But also theoretically, due to Liz's interference and omniscience among the time waves, she is equally capable of sorting out all of these other Comstocks and stopping their 'decision' as well, or any other circumstance which would foresee someone like Comstock rising up. (This is all contingent on Comstock behaving in an extremely similar way to the events in Infinite though, which limits the potential for the those specific universes in which he is able to fulfill his dream through Liz's abilities)
But doesn't travel between the multiverses cause rapid aging? There's no way that Elizabeth could sort out all other possible Comstocks before her inevitable death.
Moreover though how could she destroy the Comstock that exists in her own personal timeline, without erasing herself from existence? Even assuming that she is immune to the aging effects of interdimensional travel, that Comstock that created her would have to continue to exist.